diff --git a/plugins/OStatus/OStatusPlugin.php b/plugins/OStatus/OStatusPlugin.php
index 226e678457..a74ce6201b 100644
--- a/plugins/OStatus/OStatusPlugin.php
+++ b/plugins/OStatus/OStatusPlugin.php
@@ -245,6 +245,7 @@ class OStatusPlugin extends Plugin
                                     array('group' => $group->nickname));
             $widget->out->element('a', array('href' => $url,
                                         'class' => 'entity_remote_subscribe'),
+                                // TRANS: Link to subscribe to a remote entity.
                                 _m('Subscribe'));
 
             $output->elementEnd('li');
@@ -265,6 +266,7 @@ class OStatusPlugin extends Plugin
                                     array('tagger' => $profile->nickname, 'peopletag' => $peopletag->tag));
             $output->element('a', array('href' => $url,
                                         'class' => 'entity_remote_subscribe'),
+                                // TRANS: Link to subscribe to a remote entity.
                                 _m('Subscribe'));
 
             $output->elementEnd('li');
@@ -283,7 +285,8 @@ class OStatusPlugin extends Plugin
                                            'action' => common_local_url('tagprofile', array('id' => @$profile->id))));
 
         $action->elementStart('fieldset');
-        $action->element('legend', null, _('Tag remote profile'));
+        // TRANS: Fieldset legend.
+        $action->element('legend', null, _m('Tag remote profile'));
         $action->hidden('token', common_session_token());
 
         $user = common_current_user();
@@ -291,11 +294,14 @@ class OStatusPlugin extends Plugin
         $action->elementStart('ul', 'form_data');
         $action->elementStart('li');
 
-        $action->input('uri', _('Remote profile'), $action->trimmed('uri'),
-                     _('OStatus user\'s address, like nickname@example.com or http://example.net/nickname'));
+        // TRANS: Field label.
+        $action->input('uri', _m('LABEL','Remote profile'), $action->trimmed('uri'),
+                     // TRANS: Field title.
+                     _m('OStatus user\'s address, like nickname@example.com or http://example.net/nickname.'));
         $action->elementEnd('li');
         $action->elementEnd('ul');
-        $action->submit('fetch', _('Fetch'));
+        // TRANS: Button text to fetch remote profile.
+        $action->submit('fetch', _m('BUTTON','Fetch'));
         $action->elementEnd('fieldset');
         $action->elementEnd('form');
     }
@@ -312,7 +318,8 @@ class OStatusPlugin extends Plugin
                 } else if (Validate::uri($uri)) {
                     $oprofile = Ostatus_profile::ensureProfileURL($uri);
                 } else {
-                    throw new Exception('Invalid URI');
+                    // TRANS: Exception in OStatus when invalid URI was entered.
+                    throw new Exception(_m('Invalid URI.'));
                 }
 
                 // redirect to the new profile.
@@ -320,7 +327,8 @@ class OStatusPlugin extends Plugin
                 return false;
 
             } catch (Exception $e) {
-                $err = _m("Sorry, we could not reach that address. Please make sure that the OStatus address is like nickname@example.com or http://example.net/nickname");
+                // TRANS: Error message in OStatus plugin.
+                $err = _m("Sorry, we could not reach that address. Please make sure that the OStatus address is like nickname@example.com or http://example.net/nickname.");
             }
 
             $action->showForm($err);
@@ -346,12 +354,14 @@ class OStatusPlugin extends Plugin
                     } else if (Validate::uri($q)) {
                         $oprofile = Ostatus_profile::ensureProfileURL($q);
                     } else {
-                        throw new Exception('Invalid URI');
+                        // TRANS: Exception in OStatus when invalid URI was entered.
+                        throw new Exception(_m('Invalid URI.'));
                     }
                     return $this->filter(array($oprofile->localProfile()));
 
                 } catch (Exception $e) {
-                    $this->msg = _m("Sorry, we could not reach that address. Please make sure that the OStatus address is like nickname@example.com or http://example.net/nickname");
+                    // TRANS: Error message in OStatus plugin.
+                    $this->msg = _m("Sorry, we could not reach that address. Please make sure that the OStatus address is like nickname@example.com or http://example.net/nickname.");
                     return array();
                 }
             }
@@ -369,7 +379,6 @@ class OStatusPlugin extends Plugin
      * @param array &$mention in/out param: set of found mentions
      * @return boolean hook return value
      */
-
     function onEndFindMentions($sender, $text, &$mentions)
     {
         $matches = array();
@@ -566,12 +575,13 @@ class OStatusPlugin extends Plugin
                 }
 
                 $url = $notice->url;
-                // TRANSLATE: %s is a domain.
-                $title = sprintf(_m("Sent from %s via OStatus"), $domain);
+                // TRANS: Title.
+                // TRANS: %s is a domain name.
+                $title = sprintf(_m('Sent from %s via OStatus'), $domain);
                 return false;
             }
         }
-	return true;
+    return true;
     }
 
     /**
@@ -638,7 +648,7 @@ class OStatusPlugin extends Plugin
         }
 
         if (!$oprofile->subscribe()) {
-            // TRANS: Exception.
+            // TRANS: Exception thrown when setup of remote subscription fails.
             throw new Exception(_m('Could not set up remote subscription.'));
         }
     }
@@ -680,7 +690,7 @@ class OStatusPlugin extends Plugin
 
     /**
      * Notify remote server and garbage collect unused feeds on unsubscribe.
-     * @fixme send these operations to background queues
+     * @todo FIXME: Send these operations to background queues
      *
      * @param User $user
      * @param Profile $other
@@ -713,7 +723,8 @@ class OStatusPlugin extends Plugin
                                   common_date_iso8601(time()));
 
         $act->time    = time();
-        $act->title   = _m('Unfollow');
+        // TRANS: Title for unfollowing a remote profile.
+        $act->title   = _m('TITLE','Unfollow');
         // TRANS: Success message for unsubscribe from user attempt through OStatus.
         // TRANS: %1$s is the unsubscriber's name, %2$s is the unsubscribed user's name.
         $act->content = sprintf(_m('%1$s stopped following %2$s.'),
@@ -738,12 +749,12 @@ class OStatusPlugin extends Plugin
      *
      * @return mixed hook return value
      */
-
     function onStartJoinGroup($group, $user)
     {
         $oprofile = Ostatus_profile::staticGet('group_id', $group->id);
         if ($oprofile) {
             if (!$oprofile->subscribe()) {
+                // TRANS: Exception thrown when setup of remote group membership fails.
                 throw new Exception(_m('Could not set up remote group membership.'));
             }
 
@@ -763,7 +774,8 @@ class OStatusPlugin extends Plugin
             $act->object = $oprofile->asActivityObject();
 
             $act->time = time();
-            $act->title = _m("Join");
+            // TRANS: Title to join a remote group.
+            $act->title = _m('TITLE','Join');
             // TRANS: Success message for subscribe to group attempt through OStatus.
             // TRANS: %1$s is the member name, %2$s is the subscribed group's name.
             $act->content = sprintf(_m('%1$s has joined group %2$s.'),
@@ -774,8 +786,8 @@ class OStatusPlugin extends Plugin
                 return true;
             } else {
                 $oprofile->garbageCollect();
-                // TRANS: Exception.
-                throw new Exception(_m("Failed joining remote group."));
+                // TRANS: Exception thrown when joining a remote group fails.
+                throw new Exception(_m('Failed joining remote group.'));
             }
         }
     }
@@ -794,7 +806,6 @@ class OStatusPlugin extends Plugin
      *
      * @return mixed hook return value
      */
-
     function onEndLeaveGroup($group, $user)
     {
         $oprofile = Ostatus_profile::staticGet('group_id', $group->id);
@@ -815,7 +826,8 @@ class OStatusPlugin extends Plugin
             $act->object = $oprofile->asActivityObject();
 
             $act->time = time();
-            $act->title = _m("Leave");
+            // TRANS: Title for leaving a remote group.
+            $act->title = _m('TITLE','Leave');
             // TRANS: Success message for unsubscribe from group attempt through OStatus.
             // TRANS: %1$s is the member name, %2$s is the unsubscribed group's name.
             $act->content = sprintf(_m('%1$s has left group %2$s.'),
@@ -842,7 +854,8 @@ class OStatusPlugin extends Plugin
         $oprofile = Ostatus_profile::staticGet('peopletag_id', $peopletag->id);
         if ($oprofile) {
             if (!$oprofile->subscribe()) {
-                throw new Exception(_m('Could not set up remote peopletag subscription.'));
+                // TRANS: Exception thrown when setup of remote people tag subscription fails.
+                throw new Exception(_m('Could not set up remote people tag subscription.'));
             }
 
             $sub = $user->getProfile();
@@ -859,8 +872,11 @@ class OStatusPlugin extends Plugin
             $act->object = $oprofile->asActivityObject();
 
             $act->time = time();
-            $act->title = _m("Follow list");
-            $act->content = sprintf(_m("%s is now following people tagged %s by %s."),
+            // TRANS: Title for remote follow list.
+            $act->title = _m('TITLE','Follow list');
+            // TRANS: Success message for remote list follow through OStatus.
+            // TRANS: %1$s is the subscriber name, %2$s the prople tag, %3$s is the tagger's name.
+            $act->content = sprintf(_m("%1$s is now following people tagged %2$s by %3$s."),
                                     $sub->getBestName(),
                                     $oprofile->getBestName(),
                                     $tagger->getBestName());
@@ -869,7 +885,8 @@ class OStatusPlugin extends Plugin
                 return true;
             } else {
                 $oprofile->garbageCollect();
-                throw new Exception(_m("Failed subscribing to remote peopletag."));
+                // TRANS: Exception thrown when subscription of remote people tag fails.
+                throw new Exception(_m('Failed subscribing to remote people tag.'));
             }
         }
     }
@@ -905,8 +922,8 @@ class OStatusPlugin extends Plugin
             $act->object = $oprofile->asActivityObject();
 
             $act->time = time();
-            $act->title = _m("Unfollow peopletag");
-            $act->content = sprintf(_m("%s stopped following the list %s by %s."),
+            $act->title = _m('Unfollow people tag');
+            $act->content = sprintf(_m('%1$s stopped following the list %2$s by %3$s.'),
                                     $sub->getBestName(),
                                     $oprofile->getBestName(),
                                     $tagger->getBestName());
@@ -982,8 +999,8 @@ class OStatusPlugin extends Plugin
                                   $plist->tagger, $plist->id,
                                   common_date_iso8601(time()));
         $act->time = time();
-        $act->title = _("Tag");
-        $act->content = sprintf(_("%s tagged %s in the list %s"),
+        $act->title = _m('TITLE','Tag');
+        $act->content = sprintf(_m('%1$s tagged %2$s in the list %3$s.'),
                                 $tagger->getBestName(),
                                 $tagged->getBestName(),
                                 $plist->getBestName());
@@ -996,7 +1013,7 @@ class OStatusPlugin extends Plugin
 
         // initiate a PuSH subscription for the person being tagged
         if (!$oprofile->subscribe()) {
-            throw new Exception(sprintf(_('Could not complete subscription to remote '.
+            throw new Exception(sprintf(_m('Could not complete subscription to remote '.
                                           'profile\'s feed. Tag %s could not be saved.'), $ptag->tag));
             return false;
         }
@@ -1035,8 +1052,8 @@ class OStatusPlugin extends Plugin
                                   $plist->tagger, $plist->id,
                                   common_date_iso8601(time()));
         $act->time = time();
-        $act->title = _("Untag");
-        $act->content = sprintf(_("%s untagged %s from the list %s"),
+        $act->title = _m('TITLE','Untag');
+        $act->content = sprintf(_('%1$s untagged %2$s from the list %3$s.'),
                                 $tagger->getBestName(),
                                 $tagged->getBestName(),
                                 $plist->getBestName());
@@ -1061,7 +1078,6 @@ class OStatusPlugin extends Plugin
      *
      * @return hook return value
      */
-
     function onEndDisfavorNotice(Profile $profile, Notice $notice)
     {
         $user = User::staticGet('id', $profile->id);
@@ -1206,7 +1222,7 @@ class OStatusPlugin extends Plugin
         $act->title   = _m("Profile update");
         // TRANS: Ping text for remote profile update through OStatus.
         // TRANS: %s is user that updated their profile.
-        $act->content = sprintf(_m("%s has updated their profile page."),
+        $act->content = sprintf(_m('%s has updated their profile page.'),
                                $profile->getBestName());
 
         $act->actor   = ActivityObject::fromProfile($profile);
@@ -1317,7 +1333,7 @@ class OStatusPlugin extends Plugin
         // so we check locally first.
 
         $user = User::staticGet('uri', $uri);
-        
+
         if (!empty($user)) {
             $profile = $user->getProfile();
             return false;
@@ -1339,13 +1355,13 @@ class OStatusPlugin extends Plugin
 
     function onEndXrdActionLinks(&$xrd, $user)
     {
-    	$xrd->links[] = array('rel' => Discovery::UPDATESFROM,
-			      'href' => common_local_url('ApiTimelineUser',
-							 array('id' => $user->id,
-							       'format' => 'atom')),
-			      'type' => 'application/atom+xml');
-	
-	            // Salmon
+        $xrd->links[] = array('rel' => Discovery::UPDATESFROM,
+                  'href' => common_local_url('ApiTimelineUser',
+                             array('id' => $user->id,
+                                   'format' => 'atom')),
+                  'type' => 'application/atom+xml');
+
+                // Salmon
         $salmon_url = common_local_url('usersalmon',
                                        array('id' => $user->id));
 
@@ -1373,7 +1389,7 @@ class OStatusPlugin extends Plugin
         $url = common_local_url('ostatussub') . '?profile={uri}';
         $xrd->links[] = array('rel' => 'http://ostatus.org/schema/1.0/subscribe',
                               'template' => $url );
-	
-    	return true;
+
+        return true;
     }
 }
diff --git a/plugins/OStatus/README b/plugins/OStatus/README
index ea5dfc055f..4f839c863a 100644
--- a/plugins/OStatus/README
+++ b/plugins/OStatus/README
@@ -50,7 +50,6 @@ $config['feedsub']['nohub']
     and we have no polling backend. (The fallback hub option can be used
     with a 3rd-party service to provide such polling.)
 
-
 Todo:
 * better support for feeds that aren't natively oriented at social networking
 * make use of tags/categories from feeds
diff --git a/plugins/OStatus/actions/groupsalmon.php b/plugins/OStatus/actions/groupsalmon.php
index a9838f6e1b..d03803d620 100644
--- a/plugins/OStatus/actions/groupsalmon.php
+++ b/plugins/OStatus/actions/groupsalmon.php
@@ -53,7 +53,7 @@ class GroupsalmonAction extends SalmonAction
         $oprofile = Ostatus_profile::staticGet('group_id', $id);
         if ($oprofile) {
             // TRANS: Client error.
-            $this->clientError(_m("Can't accept remote posts for a remote group."));
+            $this->clientError(_m('Cannot accept remote posts for a remote group.'));
         }
 
         return true;
@@ -74,7 +74,7 @@ class GroupsalmonAction extends SalmonAction
             break;
         default:
             // TRANS: Client exception.
-            throw new ClientException("Can't handle that kind of post.");
+            throw new ClientException('Cannot handle that kind of post.');
         }
 
         // Notice must be to the attention of this group
@@ -127,11 +127,11 @@ class GroupsalmonAction extends SalmonAction
         $oprofile = $this->ensureProfile();
         if (!$oprofile) {
             // TRANS: Client error.
-            $this->clientError(_m("Can't read profile to set up group membership."));
+            $this->clientError(_m('Cannot read profile to set up group membership.'));
         }
         if ($oprofile->isGroup()) {
             // TRANS: Client error.
-            $this->clientError(_m("Groups can't join groups."));
+            $this->clientError(_m('Groups cannot join groups.'));
         }
 
         common_log(LOG_INFO, "Remote profile {$oprofile->uri} joining local group {$this->group->nickname}");
@@ -164,10 +164,10 @@ class GroupsalmonAction extends SalmonAction
     {
         $oprofile = $this->ensureProfile();
         if (!$oprofile) {
-            $this->clientError(_m("Can't read profile to cancel group membership."));
+            $this->clientError(_m('Cannot read profile to cancel group membership.'));
         }
         if ($oprofile->isGroup()) {
-            $this->clientError(_m("Groups can't join groups."));
+            $this->clientError(_m('Groups cannot join groups.'));
         }
 
         common_log(LOG_INFO, "Remote profile {$oprofile->uri} leaving local group {$this->group->nickname}");
diff --git a/plugins/OStatus/actions/ostatusinit.php b/plugins/OStatus/actions/ostatusinit.php
index bcef3eef29..8dc68e4b01 100644
--- a/plugins/OStatus/actions/ostatusinit.php
+++ b/plugins/OStatus/actions/ostatusinit.php
@@ -65,6 +65,7 @@ class OStatusInitAction extends Action
             /* Use a session token for CSRF protection. */
             $token = $this->trimmed('token');
             if (!$token || $token != common_session_token()) {
+                // TRANS: Client error displayed when the session token does not match or is not given.
                 $this->showForm(_m('There was a problem with your session token. '.
                                   'Try again, please.'));
                 return;
@@ -84,7 +85,7 @@ class OStatusInitAction extends Action
             $this->elementStart('html');
             $this->elementStart('head');
             // TRANS: Form title.
-            $this->element('title', null, _m('Subscribe to user'));
+            $this->element('title', null, _m('TITLE','Subscribe to user'));
             $this->elementEnd('head');
             $this->elementStart('body');
             $this->showContent();
@@ -98,18 +99,20 @@ class OStatusInitAction extends Action
     function showContent()
     {
         if ($this->group) {
-            // TRANS: Form legend.
+            // TRANS: Form legend. %s is a group name.
             $header = sprintf(_m('Join group %s'), $this->group);
+            // TRANS: Button text to join a group.
             $submit = _m('BUTTON','Join');
         } else if ($this->peopletag && $this->tagger) {
-            $header = sprintf(_m('Subscribe to people tagged %s by %s'), $this->peopletag, $this->tagger);
-            $submit = _m('Subscribe');
+            // TRANS: Form legend. %1$s is a people tag, %2$s is a tagger's name.
+            $header = sprintf(_m('Subscribe to people tagged %1$s by %2$s'), $this->peopletag, $this->tagger);
+            // TRANS: Button text to subscribe to a people tag.
             $submit = _m('BUTTON','Subscribe');
             // TRANS: Button text.
         } else {
-            // TRANS: Form legend.
+            // TRANS: Form legend. %s is a nickname.
             $header = sprintf(_m('Subscribe to %s'), $this->nickname);
-            // TRANS: Button text.
+            // TRANS: Button text to subscribe to a profile.
             $submit = _m('BUTTON','Subscribe');
         }
         $this->elementStart('form', array('id' => 'form_ostatus_connect',
@@ -126,10 +129,12 @@ class OStatusInitAction extends Action
         if ($this->group) {
             // TRANS: Field label.
             $this->input('group', _m('Group nickname'), $this->group,
+                         // TRANS: Field title.
                          _m('Nickname of the group you want to join.'));
         } else {
             // TRANS: Field label.
             $this->input('nickname', _m('User nickname'), $this->nickname,
+                         // TRANS: Field title.
                          _m('Nickname of the user you want to follow.'));
             $this->hidden('tagger', $this->tagger);
             $this->hidden('peopletag', $this->peopletag);
@@ -140,7 +145,7 @@ class OStatusInitAction extends Action
         // TRANS: Field label.
         $this->input('profile', _m('Profile Account'), $this->profile,
                       // TRANS: Tooltip for field label "Profile Account".
-                     _m('Your account id (e.g. user@identi.ca).'));
+                     _m('Your account ID (e.g. user@identi.ca).'));
         $this->elementEnd('li');
         $this->elementEnd('ul');
         $this->submit('submit', $submit);
@@ -174,7 +179,7 @@ class OStatusInitAction extends Action
         $result = $disco->lookup($acct);
         if (!$result) {
             // TRANS: Client error.
-            $this->clientError(_m("Couldn't look up OStatus account profile."));
+            $this->clientError(_m('Could not look up OStatus account profile.'));
         }
 
         foreach ($result->links as $link) {
@@ -187,7 +192,7 @@ class OStatusInitAction extends Action
 
         }
         // TRANS: Client error.
-        $this->clientError(_m("Couldn't confirm remote profile address."));
+        $this->clientError(_m('Could not confirm remote profile address.'));
     }
 
     function connectProfile($subscriber_profile)
diff --git a/plugins/OStatus/actions/ostatuspeopletag.php b/plugins/OStatus/actions/ostatuspeopletag.php
index 737a7c50f3..6d6199b811 100644
--- a/plugins/OStatus/actions/ostatuspeopletag.php
+++ b/plugins/OStatus/actions/ostatuspeopletag.php
@@ -95,7 +95,7 @@ class OStatusPeopletagAction extends OStatusSubAction
         $cur = common_current_user();
         if ($ptag->hasSubscriber($cur->id)) {
             $this->element('div', array('class' => 'error'),
-                           _m("You are already subscribed to this peopletag."));
+                           _m('You are already subscribed to this people tag.'));
             $ok = false;
         } else {
             $ok = true;
diff --git a/plugins/OStatus/actions/ostatussub.php b/plugins/OStatus/actions/ostatussub.php
index 95c6e18c18..a7726e6872 100644
--- a/plugins/OStatus/actions/ostatussub.php
+++ b/plugins/OStatus/actions/ostatussub.php
@@ -345,6 +345,7 @@ class OStatusSubAction extends Action
         // CSRF protection
         $token = $this->trimmed('token');
         if (!$token || $token != common_session_token()) {
+            // TRANS: Client error displayed when the session token does not match or is not given.
             $this->showForm(_m('There was a problem with your session token. '.
                               'Try again, please.'));
             return;
diff --git a/plugins/OStatus/actions/ostatustag.php b/plugins/OStatus/actions/ostatustag.php
index 85ead81ca2..eaf9c167e7 100644
--- a/plugins/OStatus/actions/ostatustag.php
+++ b/plugins/OStatus/actions/ostatustag.php
@@ -83,7 +83,7 @@ class OStatusTagAction extends OStatusInitAction
         $disco = new Discovery;
         $result = $disco->lookup($acct);
         if (!$result) {
-            $this->clientError(_m("Couldn't look up OStatus account profile."));
+            $this->clientError(_m('Could not look up OStatus account profile.'));
         }
 
         foreach ($result->links as $link) {
@@ -95,7 +95,7 @@ class OStatusTagAction extends OStatusInitAction
             }
 
         }
-        $this->clientError(_m("Couldn't confirm remote profile address."));
+        $this->clientError(_m('Could not confirm remote profile address.'));
     }
 
     function connectProfile($subscriber_profile)
diff --git a/plugins/OStatus/actions/peopletagsalmon.php b/plugins/OStatus/actions/peopletagsalmon.php
index c5e972e233..21025f511e 100644
--- a/plugins/OStatus/actions/peopletagsalmon.php
+++ b/plugins/OStatus/actions/peopletagsalmon.php
@@ -36,19 +36,19 @@ class PeopletagsalmonAction extends SalmonAction
         $id = $this->trimmed('id');
 
         if (!$id) {
-            $this->clientError(_('No ID.'));
+            $this->clientError(_m('No ID.'));
         }
 
         $this->peopletag = Profile_list::staticGet('id', $id);
 
         if (empty($this->peopletag)) {
-            $this->clientError(_('No such peopletag.'));
+            $this->clientError(_m('No such people tag.'));
         }
 
         $oprofile = Ostatus_profile::staticGet('peopletag_id', $id);
 
         if (!empty($oprofile)) {
-            $this->clientError(_m("Can't accept remote posts for a remote peopletag."));
+            $this->clientError(_m('Cannot accept remote posts for a remote people tag.'));
         }
 
         return true;
@@ -86,10 +86,10 @@ class PeopletagsalmonAction extends SalmonAction
     {
         $oprofile = $this->ensureProfile();
         if (!$oprofile) {
-            $this->clientError(_m("Can't read profile to set up profiletag subscription."));
+            $this->clientError(_m('Cannot read profile to set up profile tag subscription.'));
         }
         if ($oprofile->isGroup()) {
-            $this->clientError(_m("Groups can't subscribe to peopletags."));
+            $this->clientError(_m('Groups cannot subscribe to people tags.'));
         }
 
         common_log(LOG_INFO, "Remote profile {$oprofile->uri} subscribing to local peopletag ".$this->peopletag->getBestName());
@@ -107,7 +107,7 @@ class PeopletagsalmonAction extends SalmonAction
         try {
             Profile_tag_subscription::add($this->peopletag, $profile);
         } catch (Exception $e) {
-            $this->serverError(sprintf(_m('Could not subscribe remote user %1$s to peopletag %2$s.'),
+            $this->serverError(sprintf(_m('Could not subscribe remote user %1$s to people tag %2$s.'),
                                        $oprofile->uri, $this->peopletag->getBestName()));
         }
     }
@@ -120,10 +120,10 @@ class PeopletagsalmonAction extends SalmonAction
     {
         $oprofile = $this->ensureProfile();
         if (!$oprofile) {
-            $this->clientError(_m("Can't read profile to cancel peopletag membership."));
+            $this->clientError(_m('Cannot read profile to cancel people tag membership.'));
         }
         if ($oprofile->isGroup()) {
-            $this->clientError(_m("Groups can't subscribe to peopletags."));
+            $this->clientError(_m('Groups cannot subscribe to people tags.'));
         }
 
         common_log(LOG_INFO, "Remote profile {$oprofile->uri} unsubscribing from local peopletag ".$this->peopletag->getBestName());
@@ -133,7 +133,7 @@ class PeopletagsalmonAction extends SalmonAction
                 Profile_tag_subscription::remove($this->peopletag->tagger, $this->peopletag->tag, $profile->id);
 
         } catch (Exception $e) {
-            $this->serverError(sprintf(_m('Could not remove remote user %1$s from peopletag %2$s.'),
+            $this->serverError(sprintf(_m('Could not remove remote user %1$s from people tag %2$s.'),
                                        $oprofile->uri, $this->peopletag->getBestName()));
             return;
         }
diff --git a/plugins/OStatus/actions/pushhub.php b/plugins/OStatus/actions/pushhub.php
index e7716c8cd0..b2a97dbc6c 100644
--- a/plugins/OStatus/actions/pushhub.php
+++ b/plugins/OStatus/actions/pushhub.php
@@ -28,18 +28,14 @@ if (!defined('STATUSNET')) {
 }
 
 /**
-
-
-Things to consider...
-* should we purge incomplete subscriptions that never get a verification pingback?
-* when can we send subscription renewal checks?
-    - at next send time probably ok
-* when can we handle trimming of subscriptions?
-    - at next send time probably ok
-* should we keep a fail count?
-
-*/
-
+ * Things to consider...
+ * should we purge incomplete subscriptions that never get a verification pingback?
+ * when can we send subscription renewal checks?
+ *    - at next send time probably ok
+ * when can we handle trimming of subscriptions?
+ *    - at next send time probably ok
+ * should we keep a fail count?
+ */
 class PushHubAction extends Action
 {
     function arg($arg, $def=null)
@@ -95,13 +91,13 @@ class PushHubAction extends Action
 
         $verify = $this->arg('hub.verify'); // @fixme may be multiple
         if ($verify != 'sync' && $verify != 'async') {
-            // TRANS: Client exception.
+            // TRANS: Client exception. %s is sync or async.
             throw new ClientException(sprintf(_m('Invalid hub.verify "%s". It must be sync or async.'),$verify));
         }
 
         $lease = $this->arg('hub.lease_seconds', null);
         if ($mode == 'subscribe' && $lease != '' && !preg_match('/^\d+$/', $lease)) {
-            // TRANS: Client exception.
+            // TRANS: Client exception. %s is the invalid lease value.
             throw new ClientException(sprintf(_m('Invalid hub.lease "%s". It must be empty or positive integer.'),$lease));
         }
 
@@ -109,7 +105,7 @@ class PushHubAction extends Action
 
         $secret = $this->arg('hub.secret', null);
         if ($secret != '' && strlen($secret) >= 200) {
-            // TRANS: Client exception.
+            // TRANS: Client exception. %s is the invalid hub secret.
             throw new ClientException(sprintf(_m('Invalid hub.secret "%s". It must be under 200 bytes.'),$secret));
         }
 
@@ -161,8 +157,8 @@ class PushHubAction extends Action
             if ($feed == $userFeed) {
                 $user = User::staticGet('id', $id);
                 if (!$user) {
-                    // TRANS: Client exception.
-                    throw new ClientException(sprintt(_m('Invalid hub.topic "%s". User doesn\'t exist.'),$feed));
+                    // TRANS: Client exception. %s is a feed URL.
+                    throw new ClientException(sprintt(_m('Invalid hub.topic "%s". User does not exist.'),$feed));
                 } else {
                     return true;
                 }
@@ -170,8 +166,8 @@ class PushHubAction extends Action
             if ($feed == $groupFeed) {
                 $user = User_group::staticGet('id', $id);
                 if (!$user) {
-                    // TRANS: Client exception.
-                    throw new ClientException(sprintf(_m('Invalid hub.topic "%s". Group doesn\'t exist.'),$feed));
+                    // TRANS: Client exception. %s is a feed URL.
+                    throw new ClientException(sprintf(_m('Invalid hub.topic "%s". Group does not exist.'),$feed));
                 } else {
                     return true;
                 }
@@ -186,7 +182,8 @@ class PushHubAction extends Action
                 $list = Profile_list::staticGet('id', $id);
                 $user = User::staticGet('id', $user);
                 if (!$list || !$user || $list->tagger != $user->id) {
-                    throw new ClientException("Invalid hub.topic $feed; people tag doesn't exist.");
+                    // TRANS: Client exception. %s is a feed URL.
+                    throw new ClientException(sprintf(_m('Invalid hub.topic %s; people tag does not exist.'),$feed));
                 } else {
                     return true;
                 }
diff --git a/plugins/OStatus/actions/usersalmon.php b/plugins/OStatus/actions/usersalmon.php
index f5a93183e5..41b688af56 100644
--- a/plugins/OStatus/actions/usersalmon.php
+++ b/plugins/OStatus/actions/usersalmon.php
@@ -67,7 +67,7 @@ class UsersalmonAction extends SalmonAction
         case ActivityObject::COMMENT:
             break;
         default:
-            throw new ClientException("Can't handle that kind of post.");
+            throw new ClientException(_m('Cannot handle that kind of post.'));
         }
 
         // Notice must either be a) in reply to a notice by this user
@@ -255,7 +255,7 @@ class UsersalmonAction extends SalmonAction
     {
         if (!$object) {
             // TRANS: Client exception.
-            throw new ClientException(_m('Can\'t favorite/unfavorite without an object.'));
+            throw new ClientException(_m('Cannot favorite/unfavorite without an object.'));
         }
 
         switch ($object->type) {
@@ -267,7 +267,7 @@ class UsersalmonAction extends SalmonAction
             break;
         default:
             // TRANS: Client exception.
-            throw new ClientException(_m('Can\'t handle that kind of object for liking/faving.'));
+            throw new ClientException(_m('Cannot handle that kind of object for liking/faving.'));
         }
 
         $notice = Notice::staticGet('uri', $object->id);
diff --git a/plugins/OStatus/classes/FeedSub.php b/plugins/OStatus/classes/FeedSub.php
index 7756f6a234..7da8dcd7ee 100644
--- a/plugins/OStatus/classes/FeedSub.php
+++ b/plugins/OStatus/classes/FeedSub.php
@@ -249,6 +249,7 @@ class FeedSub extends Memcached_DataObject
                 // We'll never actually get updates in this mode.
                 return true;
             } else {
+                // TRANS: Server exception.
                 throw new ServerException(_m('Attempting to start PuSH subscription for feed with no hub.'));
             }
         }
@@ -279,6 +280,7 @@ class FeedSub extends Memcached_DataObject
                 // We'll never actually get updates in this mode.
                 return true;
             } else {
+                // TRANS: Server exception.
                 throw new ServerException(_m('Attempting to end PuSH subscription for feed with no hub.'));
             }
         }
diff --git a/plugins/OStatus/classes/Ostatus_profile.php b/plugins/OStatus/classes/Ostatus_profile.php
index 821ebef3d5..7e7170d14c 100644
--- a/plugins/OStatus/classes/Ostatus_profile.php
+++ b/plugins/OStatus/classes/Ostatus_profile.php
@@ -53,7 +53,6 @@ class Ostatus_profile extends Managed_DataObject
      *
      * @return array array of column definitions
      */
-
     static function schemaDef()
     {
         return array(
@@ -172,10 +171,10 @@ class Ostatus_profile extends Managed_DataObject
             return true;
         } else if ($this->group_id && ($this->profile_id || $this->peopletag_id)) {
             // TRANS: Server exception. %s is a URI
-            throw new ServerException(_m("Invalid ostatus_profile state: two or more IDs set for %s", $this->uri));
+            throw new ServerException(sprintf(_m('Invalid ostatus_profile state: two or more IDs set for %s'), $this->uri));
         } else {
             // TRANS: Server exception. %s is a URI
-            throw new ServerException(_m("Invalid ostatus_profile state: all IDs empty for %s", $this->uri));
+            throw new ServerException(sprintf(_m('Invalid ostatus_profile state: all IDs empty for %s.'), $this->uri));
         }
     }
 
@@ -190,10 +189,10 @@ class Ostatus_profile extends Managed_DataObject
             return true;
         } else if ($this->peopletag_id && ($this->profile_id || $this->group_id)) {
             // TRANS: Server exception. %s is a URI
-            throw new ServerException(_m("Invalid ostatus_profile state: two or more IDs set for %s", $this->uri));
+            throw new ServerException(sprintf(_m('Invalid ostatus_profile state: two or more IDs set for %s'), $this->uri));
         } else {
             // TRANS: Server exception. %s is a URI
-            throw new ServerException(_m("Invalid ostatus_profile state: all IDs empty for %s", $this->uri));
+            throw new ServerException(sprintf(_m('Invalid ostatus_profile state: all IDs empty for %s.'), $this->uri));
         }
     }
 
@@ -296,7 +295,6 @@ class Ostatus_profile extends Managed_DataObject
             $object = $this;
         }
         if ($this->salmonuri) {
-
             $text = 'update';
             $id = TagURI::mint('%s:%s:%s',
                                $verb,
@@ -466,14 +464,12 @@ class Ostatus_profile extends Managed_DataObject
      * @param DOMElement $feed for context
      * @param string $source identifier ("push" or "salmon")
      */
-
     public function processEntry($entry, $feed, $source)
     {
         $activity = new Activity($entry, $feed);
 
         if (Event::handle('StartHandleFeedEntryWithProfile', array($activity, $this)) &&
             Event::handle('StartHandleFeedEntry', array($activity))) {
-
             // @todo process all activity objects
             switch ($activity->objects[0]->type) {
             case ActivityObject::ARTICLE:
@@ -481,7 +477,7 @@ class Ostatus_profile extends Managed_DataObject
             case ActivityObject::NOTE:
             case ActivityObject::STATUS:
             case ActivityObject::COMMENT:
-			case null:
+            case null:
                 if ($activity->verb == ActivityVerb::POST) {
                     $this->processPost($activity, $source);
                 } else {
@@ -490,7 +486,7 @@ class Ostatus_profile extends Managed_DataObject
                 break;
             default:
                 // TRANS: Client exception.
-                throw new ClientException(_m('Can\'t handle that kind of post.'));
+                throw new ClientException(_m('Cannot handle that kind of post.'));
             }
 
             Event::handle('EndHandleFeedEntry', array($activity));
@@ -580,7 +576,7 @@ class Ostatus_profile extends Managed_DataObject
                 // We mark up the attachment link specially for the HTML output
                 // so we can fold-out the full version inline.
 
-                // @fixme I18N this tooltip will be saved with the site's default language
+                // @todo FIXME i18n: This tooltip will be saved with the site's default language
                 // TRANS: Shown when a notice is longer than supported and/or when attachments are present. At runtime
                 // TRANS: this will usually be replaced with localised text from StatusNet core messages.
                 $showMoreText = _m('Show more');
@@ -761,7 +757,6 @@ class Ostatus_profile extends Managed_DataObject
      * @throws Exception on various error conditions
      * @throws OStatusShadowException if this reference would obscure a local user/group
      */
-
     public static function ensureProfileURL($profile_url, $hints=array())
     {
         $oprofile = self::getFromProfileURL($profile_url);
@@ -930,7 +925,6 @@ class Ostatus_profile extends Managed_DataObject
      * @return Ostatus_profile
      * @throws Exception
      */
-
     public static function ensureAtomFeed($feedEl, $hints)
     {
         $author = ActivityUtils::getFeedAuthor($feedEl);
@@ -938,7 +932,7 @@ class Ostatus_profile extends Managed_DataObject
         if (empty($author)) {
             // XXX: make some educated guesses here
             // TRANS: Feed sub exception.
-            throw new FeedSubException(_m('Can\'t find enough profile '.
+            throw new FeedSubException(_m('Cannot find enough profile '.
                                           'information to make a feed.'));
         }
 
@@ -1002,7 +996,7 @@ class Ostatus_profile extends Managed_DataObject
         }
         if (!common_valid_http_url($url)) {
             // TRANS: Server exception. %s is a URL.
-            throw new ServerException(sprintf(_m("Invalid avatar URL %s."), $url));
+            throw new ServerException(sprintf(_m('Invalid avatar URL %s.'), $url));
         }
 
         if ($this->isGroup()) {
@@ -1013,7 +1007,7 @@ class Ostatus_profile extends Managed_DataObject
         if (!$self) {
             throw new ServerException(sprintf(
                 // TRANS: Server exception. %s is a URI.
-                _m("Tried to update avatar for unsaved remote profile %s."),
+                _m('Tried to update avatar for unsaved remote profile %s.'),
                 $this->uri));
         }
 
@@ -1023,7 +1017,7 @@ class Ostatus_profile extends Managed_DataObject
         try {
             if (!copy($url, $temp_filename)) {
                 // TRANS: Server exception. %s is a URL.
-                throw new ServerException(sprintf(_m("Unable to fetch avatar from %s."), $url));
+                throw new ServerException(sprintf(_m('Unable to fetch avatar from %s.'), $url));
             }
 
             if ($this->isGroup()) {
@@ -1064,7 +1058,6 @@ class Ostatus_profile extends Managed_DataObject
      * @param array $hints
      * @return mixed URL string or false
      */
-
     public static function getActivityObjectAvatar($object, $hints=array())
     {
         if ($object->avatarLinks) {
@@ -1094,7 +1087,6 @@ class Ostatus_profile extends Managed_DataObject
      * @param DOMElement $feed
      * @return string
      */
-
     protected static function getAvatar($actor, $feed)
     {
         $url = '';
@@ -1146,7 +1138,6 @@ class Ostatus_profile extends Managed_DataObject
      * @return Ostatus_profile
      * @throws Exception
      */
-
     public static function ensureActorProfile($activity, $hints=array())
     {
         return self::ensureActivityObjectProfile($activity->actor, $hints);
@@ -1163,7 +1154,6 @@ class Ostatus_profile extends Managed_DataObject
      * @return Ostatus_profile
      * @throws Exception
      */
-
     public static function ensureActivityObjectProfile($object, $hints=array())
     {
         $profile = self::getActivityObjectProfile($object);
@@ -1244,25 +1234,25 @@ class Ostatus_profile extends Managed_DataObject
 
         if (!$homeuri) {
             common_log(LOG_DEBUG, __METHOD__ . " empty actor profile URI: " . var_export($activity, true));
-            throw new Exception("No profile URI");
+            throw new Exception('No profile URI.');
         }
 
         $user = User::staticGet('uri', $homeuri);
         if ($user) {
             // TRANS: Exception.
-            throw new Exception(_m('Local user can\'t be referenced as remote.'));
+            throw new Exception(_m('Local user cannot be referenced as remote.'));
         }
 
         if (OStatusPlugin::localGroupFromUrl($homeuri)) {
             // TRANS: Exception.
-            throw new Exception(_m('Local group can\'t be referenced as remote.'));
+            throw new Exception(_m('Local group cannot be referenced as remote.'));
         }
 
         $ptag = Profile_list::staticGet('uri', $homeuri);
         if ($ptag) {
             $local_user = User::staticGet('id', $ptag->tagger);
             if (!empty($local_user)) {
-                throw new Exception("Local peopletag can't be referenced as remote.");
+                throw new Exception('Local people tag cannot be referenced as remote.');
             }
         }
 
@@ -1315,7 +1305,7 @@ class Ostatus_profile extends Managed_DataObject
             $oprofile->profile_id = $profile->insert();
             if (!$oprofile->profile_id) {
             // TRANS: Server exception.
-                throw new ServerException(_m('Can\'t save local profile.'));
+                throw new ServerException(_m('Cannot save local profile.'));
             }
         } else if ($object->type == ActivityObject::GROUP) {
             $group = new User_group();
@@ -1326,7 +1316,7 @@ class Ostatus_profile extends Managed_DataObject
             $oprofile->group_id = $group->insert();
             if (!$oprofile->group_id) {
                 // TRANS: Server exception.
-                throw new ServerException(_m('Can\'t save local profile.'));
+                throw new ServerException(_m('Cannot save local profile.'));
             }
         } else if ($object->type == ActivityObject::_LIST) {
             $ptag = new Profile_list();
@@ -1336,7 +1326,7 @@ class Ostatus_profile extends Managed_DataObject
 
             $oprofile->peopletag_id = $ptag->insert();
             if (!$oprofile->peopletag_id) {
-                throw new ServerException("Can't save local peopletag");
+                throw new ServerException('Cannot save local people tag.');
             }
         }
 
@@ -1344,7 +1334,7 @@ class Ostatus_profile extends Managed_DataObject
 
         if (!$ok) {
             // TRANS: Server exception.
-            throw new ServerException(_m('Can\'t save OStatus profile.'));
+            throw new ServerException(_m('Cannot save OStatus profile.'));
         }
 
         $avatar = self::getActivityObjectAvatar($object, $hints);
@@ -1666,7 +1656,6 @@ class Ostatus_profile extends Managed_DataObject
         }
 
         // Try looking it up
-
         $oprofile = Ostatus_profile::staticGet('uri', 'acct:'.$addr);
 
         if (!empty($oprofile)) {
@@ -1695,7 +1684,6 @@ class Ostatus_profile extends Managed_DataObject
         $hints = array_merge($hints, $dhints);
 
         // If there's an Hcard, let's grab its info
-
         if (array_key_exists('hcard', $hints)) {
             if (!array_key_exists('profileurl', $hints) ||
                 $hints['hcard'] != $hints['profileurl']) {
@@ -1705,7 +1693,6 @@ class Ostatus_profile extends Managed_DataObject
         }
 
         // If we got a feed URL, try that
-
         if (array_key_exists('feedurl', $hints)) {
             try {
                 common_log(LOG_INFO, "Discovery on acct:$addr with feed URL " . $hints['feedurl']);
@@ -1719,7 +1706,6 @@ class Ostatus_profile extends Managed_DataObject
         }
 
         // If we got a profile page, try that!
-
         if (array_key_exists('profileurl', $hints)) {
             try {
                 common_log(LOG_INFO, "Discovery on acct:$addr with profile URL $profileUrl");
@@ -1767,7 +1753,7 @@ class Ostatus_profile extends Managed_DataObject
             if (!$profile_id) {
                 common_log_db_error($profile, 'INSERT', __FILE__);
                 // TRANS: Exception. %s is a webfinger address.
-                throw new Exception(sprintf(_m('Couldn\'t save profile for "%s".'),$addr));
+                throw new Exception(sprintf(_m('Could not save profile for "%s".'),$addr));
             }
 
             $oprofile = new Ostatus_profile();
@@ -1786,7 +1772,7 @@ class Ostatus_profile extends Managed_DataObject
             if (!$result) {
                 common_log_db_error($oprofile, 'INSERT', __FILE__);
                 // TRANS: Exception. %s is a webfinger address.
-                throw new Exception(sprintf(_m('Couldn\'t save ostatus_profile for "%s".'),$addr));
+                throw new Exception(sprintf(_m('Could not save ostatus_profile for "%s".'),$addr));
             }
 
             self::cacheSet(sprintf('ostatus_profile:webfinger:%s', $addr), $oprofile->uri);
@@ -1794,7 +1780,7 @@ class Ostatus_profile extends Managed_DataObject
         }
 
         // TRANS: Exception. %s is a webfinger address.
-        throw new Exception(sprintf(_m('Couldn\'t find a valid profile for "%s".'),$addr));
+        throw new Exception(sprintf(_m('Could not find a valid profile for "%s".'),$addr));
     }
 
     /**
@@ -1867,11 +1853,16 @@ class Ostatus_profile extends Managed_DataObject
                     $oprofile = Ostatus_profile::ensureWebfinger($rest);
                     break;
                 default:
-                    throw new ServerException("Unrecognized URI protocol for profile: $protocol ($uri)");
+                    // TRANS: Server exception.
+                    // TRANS: %1$s is a protocol, %2$s is a URI.
+                    throw new ServerException(sprintf(_m('Unrecognized URI protocol for profile: %1$s (%2$s).'),
+                                                      $protocol,
+                                                      $uri));
                     break;
                 }
             } else {
-                throw new ServerException("No URI protocol for profile: ($uri)");
+                // TRANS: Server exception. %s is a URI.
+                throw new ServerException(sprintf(_m('No URI protocol for profile: %s.'),$uri));
             }
         }
 
diff --git a/plugins/OStatus/lib/magicenvelope.php b/plugins/OStatus/lib/magicenvelope.php
index 384506280d..487435927d 100644
--- a/plugins/OStatus/lib/magicenvelope.php
+++ b/plugins/OStatus/lib/magicenvelope.php
@@ -26,7 +26,6 @@
  * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
  * @link      http://status.net/
  */
-
 class MagicEnvelope
 {
     const ENCODING = 'base64url';
@@ -327,4 +326,3 @@ class MagicEnvelopeCompat extends MagicEnvelope {
         return $env['data'];
     }
 }
-
diff --git a/plugins/OStatus/lib/salmonaction.php b/plugins/OStatus/lib/salmonaction.php
index 774709d6f5..bf9f316d54 100644
--- a/plugins/OStatus/lib/salmonaction.php
+++ b/plugins/OStatus/lib/salmonaction.php
@@ -123,7 +123,7 @@ class SalmonAction extends Action
                 break;
             default:
                 // TRANS: Client exception.
-                throw new ClientException(_m("Unrecognized activity type."));
+                throw new ClientException(_m('Unrecognized activity type.'));
             }
             Event::handle('EndHandleSalmon', array($this->activity));
             Event::handle('EndHandleSalmonTarget', array($this->activity, $this->target));
@@ -133,59 +133,61 @@ class SalmonAction extends Action
     function handlePost()
     {
         // TRANS: Client exception.
-        throw new ClientException(_m("This target doesn't understand posts."));
+        throw new ClientException(_m('This target does not understand posts.'));
     }
 
     function handleFollow()
     {
         // TRANS: Client exception.
-        throw new ClientException(_m("This target doesn't understand follows."));
+        throw new ClientException(_m('This target does not understand follows.'));
     }
 
     function handleUnfollow()
     {
         // TRANS: Client exception.
-        throw new ClientException(_m("This target doesn't understand unfollows."));
+        throw new ClientException(_m('This target does not understand unfollows.'));
     }
 
     function handleFavorite()
     {
         // TRANS: Client exception.
-        throw new ClientException(_m("This target doesn't understand favorites."));
+        throw new ClientException(_m('This target does not understand favorites.'));
     }
 
     function handleUnfavorite()
     {
         // TRANS: Client exception.
-        throw new ClientException(_m("This target doesn't understand unfavorites."));
+        throw new ClientException(_m('This target does not understand unfavorites.'));
     }
 
     function handleShare()
     {
         // TRANS: Client exception.
-        throw new ClientException(_m("This target doesn't understand share events."));
+        throw new ClientException(_m('This target does not understand share events.'));
     }
 
     function handleJoin()
     {
         // TRANS: Client exception.
-        throw new ClientException(_m("This target doesn't understand joins."));
+        throw new ClientException(_m('This target does not understand joins.'));
     }
 
     function handleLeave()
     {
         // TRANS: Client exception.
-        throw new ClientException(_m("This target doesn't understand leave events."));
+        throw new ClientException(_m('This target does not understand leave events.'));
     }
 
     function handleTag()
     {
-        throw new ClientException(_m("This target doesn't understand tag events."));
+        // TRANS: Client exception.
+        throw new ClientException(_m('This target does not understand tag events.'));
     }
 
     function handleUntag()
     {
-        throw new ClientException(_m("This target doesn't understand untag events."));
+        // TRANS: Client exception.
+        throw new ClientException(_m('This target does not understand untag events.'));
     }
 
     /**