diff --git a/actions/passwordsettings.php b/actions/passwordsettings.php
index 37877931ea..63acba7134 100644
--- a/actions/passwordsettings.php
+++ b/actions/passwordsettings.php
@@ -55,7 +55,8 @@ class PasswordsettingsAction extends SettingsAction
 
     function title()
     {
-        return _('Change password');
+        // TRANS: Title for page where to change password.
+        return _m('TITLE','Change password');
     }
 
     /**
@@ -66,6 +67,7 @@ class PasswordsettingsAction extends SettingsAction
 
     function getInstructions()
     {
+        // TRANS: Instructions for page where to change password.
         return _('Change your password.');
     }
 
@@ -93,6 +95,7 @@ class PasswordsettingsAction extends SettingsAction
                                           'action' =>
                                           common_local_url('passwordsettings')));
         $this->elementStart('fieldset');
+        // TRANS: Fieldset legend on page where to change password.
         $this->element('legend', null, _('Password change'));
         $this->hidden('token', common_session_token());
 
@@ -101,20 +104,26 @@ class PasswordsettingsAction extends SettingsAction
         // Users who logged in with OpenID won't have a pwd
         if ($user->password) {
             $this->elementStart('li');
+            // TRANS: Field label on page where to change password.
             $this->password('oldpassword', _('Old password'));
             $this->elementEnd('li');
         }
         $this->elementStart('li');
+        // TRANS: Field label on page where to change password.
         $this->password('newpassword', _('New password'),
+                        // TRANS: Field title on page where to change password.
                         _('6 or more characters.'));
         $this->elementEnd('li');
         $this->elementStart('li');
-        $this->password('confirm', _('Confirm'),
+        // TRANS: Field label on page where to change password. In this field the new password should be typed a second time.
+        $this->password('confirm', _m('LABEL','Confirm'),
+                        // TRANS: Field title on page where to change password.
                         _('Same as password above.'));
         $this->elementEnd('li');
         $this->elementEnd('ul');
 
-        $this->submit('changepass', _('Change'));
+        // TRANS: Button text on page where to change password.
+        $this->submit('changepass', _m('BUTTON','Change'));
 
         $this->elementEnd('fieldset');
         $this->elementEnd('form');
@@ -150,6 +159,7 @@ class PasswordsettingsAction extends SettingsAction
         # Some validation
 
         if (strlen($newpassword) < 6) {
+            // TRANS: Form validation error on page where to change password.
             $this->showForm(_('Password must be 6 or more characters.'));
             return;
         } else if (0 != strcmp($newpassword, $confirm)) {
@@ -161,7 +171,8 @@ class PasswordsettingsAction extends SettingsAction
             $oldpassword = $this->arg('oldpassword');
 
             if (!common_check_user($user->nickname, $oldpassword)) {
-                $this->showForm(_('Incorrect old password'));
+                // TRANS: Form validation error on page where to change password.
+                $this->showForm(_('Incorrect old password.'));
                 return;
             }
         }else{
@@ -177,17 +188,21 @@ class PasswordsettingsAction extends SettingsAction
 
             $val = $user->validate();
             if ($val !== true) {
+                // TRANS: Form validation error on page where to change password.
                 $this->showForm(_('Error saving user; invalid.'));
                 return;
             }
 
             if (!$user->update($original)) {
-                $this->serverError(_('Cannot save new password.'));
+            // TRANS: Server error displayed on page where to change password when password change
+            // TRANS: could not be made because of a server error.
+            $this->serverError(_('Cannot save new password.'));
                 return;
             }
             Event::handle('EndChangePassword', array($user));
         }
 
+        // TRANS: Form validation notice on page where to change password.
         $this->showForm(_('Password saved.'), true);
     }
 }
diff --git a/actions/pathsadminpanel.php b/actions/pathsadminpanel.php
index dd65a7a134..7bcc3f7811 100644
--- a/actions/pathsadminpanel.php
+++ b/actions/pathsadminpanel.php
@@ -152,7 +152,7 @@ class PathsadminpanelAction extends AdminPanelAction
         if (!empty($values['theme']['dir']) && !is_readable($values['theme']['dir'])) {
             // TRANS: Client error in Paths admin panel.
             // TRANS: %s is the directory that could not be read from.
-            $this->clientError(sprintf(_("Theme directory not readable: %s."), $values['theme']['dir']));
+            $this->clientError(sprintf(_('Theme directory not readable: %s.'), $values['theme']['dir']));
         }
 
         // Validate avatar dir
@@ -160,7 +160,7 @@ class PathsadminpanelAction extends AdminPanelAction
         if (empty($values['avatar']['dir']) || !is_writable($values['avatar']['dir'])) {
             // TRANS: Client error in Paths admin panel.
             // TRANS: %s is the avatar directory that could not be written to.
-            $this->clientError(sprintf(_("Avatar directory not writable: %s."), $values['avatar']['dir']));
+            $this->clientError(sprintf(_('Avatar directory not writable: %s.'), $values['avatar']['dir']));
         }
 
         // Validate background dir
@@ -168,7 +168,7 @@ class PathsadminpanelAction extends AdminPanelAction
         if (empty($values['background']['dir']) || !is_writable($values['background']['dir'])) {
             // TRANS: Client error in Paths admin panel.
             // TRANS: %s is the background directory that could not be written to.
-            $this->clientError(sprintf(_("Background directory not writable: %s."), $values['background']['dir']));
+            $this->clientError(sprintf(_('Background directory not writable: %s.'), $values['background']['dir']));
         }
 
         // Validate locales dir
@@ -178,7 +178,7 @@ class PathsadminpanelAction extends AdminPanelAction
         if (!empty($values['site']['locale_path']) && !is_readable($values['site']['locale_path'])) {
             // TRANS: Client error in Paths admin panel.
             // TRANS: %s is the locales directory that could not be read from.
-            $this->clientError(sprintf(_("Locales directory not readable: %s."), $values['site']['locale_path']));
+            $this->clientError(sprintf(_('Locales directory not readable: %s.'), $values['site']['locale_path']));
         }
 
         // Validate SSL setup
@@ -239,6 +239,7 @@ class PathsAdminPanelForm extends AdminForm
         $this->input('server',
                      // TRANS: Field label in Paths admin panel.
                      _('Server'),
+                     // TRANS: Field title in Paths admin panel.
                      _('Site\'s server hostname.'));
         $this->unli();
 
@@ -246,6 +247,7 @@ class PathsAdminPanelForm extends AdminForm
         $this->input('path',
                      // TRANS: Field label in Paths admin panel.
                      _('Path'),
+                     // TRANS: Field title in Paths admin panel.
                      _('Site path.'));
         $this->unli();
 
@@ -253,6 +255,7 @@ class PathsAdminPanelForm extends AdminForm
         $this->input('locale_path',
                      // TRANS: Field label in Paths admin panel.
                      _('Locale directory'),
+                     // TRANS: Field title in Paths admin panel.
                      _('Directory path to locales.'),
                      'site');
         $this->unli();
@@ -262,14 +265,16 @@ class PathsAdminPanelForm extends AdminForm
                              // TRANS: Checkbox label in Paths admin panel.
                              _('Fancy URLs'),
                              (bool) $this->value('fancy'),
-                             _('Use fancy (more readable and memorable) URLs?'));
+                             // TRANS: Field title in Paths admin panel.
+                             _('Use fancy URLs (more readable and memorable)?'));
         $this->unli();
 
         $this->out->elementEnd('ul');
         $this->out->elementEnd('fieldset');
 
         $this->out->elementStart('fieldset', array('id' => 'settings_paths_theme'));
-        $this->out->element('legend', null, _('Theme'));
+        // TRANS: Fieldset legend in Paths admin panel.
+        $this->out->element('legend', null, _m('LEGEND','Theme'));
 
         $this->out->elementStart('ul', 'form_data');
 
@@ -469,7 +474,7 @@ class PathsAdminPanelForm extends AdminForm
 
         $this->out->elementStart('fieldset', array('id' => 'settings_admin_ssl'));
         // TRANS: Fieldset legend in Paths admin panel.
-        $this->out->element('legend', null, _('SSL'));
+        $this->out->element('legend', null, _m('LEGEND','SSL'));
         $this->out->elementStart('ul', 'form_data');
         $this->li();
 
diff --git a/actions/peopletag.php b/actions/peopletag.php
index 7287cfbf99..2adc24ea66 100644
--- a/actions/peopletag.php
+++ b/actions/peopletag.php
@@ -44,7 +44,6 @@ if (!defined('STATUSNET') && !defined('LACONICA')) {
  *
  * @see      Action
  */
-
 class PeopletagAction extends Action
 {
 
@@ -65,6 +64,8 @@ class PeopletagAction extends Action
         $this->tag = $this->trimmed('tag');
 
         if (!common_valid_profile_tag($this->tag)) {
+            // TRANS: Client error displayed when trying to tag a profile with an invalid tag.
+            // TRANS: %s is the invalid tag.
             $this->clientError(sprintf(_('Not a valid people tag: %s.'),
                 $this->tag));
             return;
@@ -139,10 +140,11 @@ class PeopletagAction extends Action
      */
     function title()
     {
+        // TRANS: Page title for users with a certain self-tag.
+        // TRANS: %1$s is the tag, %2$s is the page number.
         return sprintf(_('Users self-tagged with %1$s - page %2$d'),
             $this->tag, $this->page);
     }
-
 }
 
 class PeopleTagList extends ProfileList
@@ -177,4 +179,3 @@ class PeopleTagListItem extends ProfileListItem
         return $aAttrs;
     }
 }
-
diff --git a/actions/plugindisable.php b/actions/plugindisable.php
index 7f107b3335..abda2a7395 100644
--- a/actions/plugindisable.php
+++ b/actions/plugindisable.php
@@ -52,7 +52,6 @@ if (!defined('STATUSNET')) {
  * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
  * @link      http://status.net/
  */
-
 class PluginDisableAction extends PluginEnableAction
 {
     /**
@@ -74,5 +73,3 @@ class PluginDisableAction extends PluginEnableAction
         return new EnablePluginForm($this, $this->plugin);
     }
 }
-
-
diff --git a/actions/pluginenable.php b/actions/pluginenable.php
index 2dbb3e3956..0f2b4ba670 100644
--- a/actions/pluginenable.php
+++ b/actions/pluginenable.php
@@ -52,7 +52,6 @@ if (!defined('STATUSNET')) {
  * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
  * @link      http://status.net/
  */
-
 class PluginEnableAction extends Action
 {
     var $user;
@@ -65,7 +64,6 @@ class PluginEnableAction extends Action
      *
      * @return boolean success flag
      */
-
     function prepare($args)
     {
         parent::prepare($args);
@@ -75,6 +73,8 @@ class PluginEnableAction extends Action
         // Only allow POST requests
 
         if ($_SERVER['REQUEST_METHOD'] != 'POST') {
+            // TRANS: Client error displayed when trying to use another method than POST.
+            // TRANS: Do not translate POST.
             $this->clientError(_('This action only accepts POST requests.'));
             return false;
         }
@@ -94,11 +94,13 @@ class PluginEnableAction extends Action
         $this->user = common_current_user();
 
         if (empty($this->user)) {
+            // TRANS: Client error displayed when trying to enable or disable a plugin while not logged in.
             $this->clientError(_('Not logged in.'));
             return false;
         }
 
         if (!AdminPanelAction::canAdmin('plugins')) {
+            // TRANS: Client error displayed when trying to enable or disable a plugin without access rights.
             $this->clientError(_('You cannot administer plugins.'));
             return false;
         }
@@ -106,6 +108,7 @@ class PluginEnableAction extends Action
         $this->plugin = $this->arg('plugin');
         $defaultPlugins = common_config('plugins', 'default');
         if (!array_key_exists($this->plugin, $defaultPlugins)) {
+            // TRANS: Client error displayed when trying to enable or disable a non-existing plugin.
             $this->clientError(_('No such plugin.'));
             return false;
         }
@@ -122,7 +125,6 @@ class PluginEnableAction extends Action
      *
      * @return void
      */
-
     function handle($args)
     {
         $key = 'disable-' . $this->plugin;
diff --git a/actions/pluginsadminpanel.php b/actions/pluginsadminpanel.php
index bc400bd514..ec8aed8a22 100644
--- a/actions/pluginsadminpanel.php
+++ b/actions/pluginsadminpanel.php
@@ -40,20 +40,17 @@ if (!defined('STATUSNET')) {
  * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
  * @link     http://status.net/
  */
-
 class PluginsadminpanelAction extends AdminPanelAction
 {
-
     /**
      * Returns the page title
      *
      * @return string page title
      */
-
     function title()
     {
         // TRANS: Tab and title for plugins admin panel.
-        return _('Plugins');
+        return _m('TITLE','Plugins');
     }
 
     /**
@@ -61,11 +58,10 @@ class PluginsadminpanelAction extends AdminPanelAction
      *
      * @return string instructions
      */
-
     function getInstructions()
     {
         // TRANS: Instructions at top of plugin admin page.
-        return _('Additional plugins can be enabled and configured manually. ' . 
+        return _('Additional plugins can be enabled and configured manually. ' .
                  'See the <a href="http://status.net/wiki/Plugins">online plugin ' .
                  'documentation</a> for more details.');
     }
@@ -75,11 +71,10 @@ class PluginsadminpanelAction extends AdminPanelAction
      *
      * @return void
      */
-
     function showForm()
     {
         $this->elementStart('fieldset', array('id' => 'settings_plugins_default'));
-        
+
         // TRANS: Admin form section header
         $this->element('legend', null, _('Default plugins'), 'default');
 
@@ -103,6 +98,7 @@ class PluginsadminpanelAction extends AdminPanelAction
             $list->show();
         } else {
             $this->element('p', null,
+                           // TRANS: Text displayed on plugin admin page when no plugin are enabled.
                            _('All default plugins have been disabled from the ' .
                              'site\'s configuration file.'));
         }
diff --git a/actions/postnotice.php b/actions/postnotice.php
index 694c7808d9..43c764aa63 100644
--- a/actions/postnotice.php
+++ b/actions/postnotice.php
@@ -92,16 +92,18 @@ class PostnoticeAction extends Action
     {
         $content = common_shorten_links($_POST['omb_notice_content']);
         if (Notice::contentTooLong($content)) {
+            // TRANS: Client error displayed if the notice posted has too many characters.
             $this->clientError(_('Invalid notice content.'), 400);
             return false;
         }
         $license      = $_POST['omb_notice_license'];
         $site_license = common_config('license', 'url');
         if ($license && !common_compatible_license($license, $site_license)) {
-            throw new Exception(sprintf(_('Notice license ‘%1$s’ is not ' .
-                                          'compatible with site license ‘%2$s’.'),
+            // TRANS: Exception thrown if a notice's license is not compatible with the StatusNet site license.
+            // TRANS: %1$s is the notice license, %2$s is the StatusNet site's license.
+            throw new Exception(sprintf(_('Notice license "%1$s" is not ' .
+                                          'compatible with site license "%2$s".'),
                                         $license, $site_license));
         }
     }
 }
-?>
\ No newline at end of file
diff --git a/actions/public.php b/actions/public.php
index adeb58b0ee..b029407250 100644
--- a/actions/public.php
+++ b/actions/public.php
@@ -51,7 +51,6 @@ define('MAX_PUBLIC_PAGE', 100);
  * @see      PublicrssAction
  * @see      PublicxrdsAction
  */
-
 class PublicAction extends Action
 {
     /**
@@ -73,14 +72,15 @@ class PublicAction extends Action
      *
      * @return boolean success value
      */
-
     function prepare($args)
     {
         parent::prepare($args);
         $this->page = ($this->arg('page')) ? ($this->arg('page')+0) : 1;
 
         if ($this->page > MAX_PUBLIC_PAGE) {
-            $this->clientError(sprintf(_("Beyond the page limit (%s)."), MAX_PUBLIC_PAGE));
+            // TRANS: Client error displayed when requesting a public timeline page beyond the page limit.
+            // TRANS: %s is the page limit.
+            $this->clientError(sprintf(_('Beyond the page limit (%s).'), MAX_PUBLIC_PAGE));
         }
 
         common_set_returnto($this->selfUrl());
@@ -89,12 +89,13 @@ class PublicAction extends Action
                                        NOTICES_PER_PAGE + 1);
 
         if (!$this->notice) {
+            // TRANS: Server error displayed when a public timeline cannot be retrieved.
             $this->serverError(_('Could not retrieve public stream.'));
             return;
         }
 
         if($this->page > 1 && $this->notice->N == 0){
-            // TRANS: Server error when page not found (404)
+            // TRANS: Server error when page not found (404).
             $this->serverError(_('No such page.'),$code=404);
         }
 
@@ -110,7 +111,6 @@ class PublicAction extends Action
      *
      * @return void
      */
-
     function handle($args)
     {
         parent::handle($args);
@@ -123,12 +123,14 @@ class PublicAction extends Action
      *
      * @return page title, including page number if over 1
      */
-
     function title()
     {
         if ($this->page > 1) {
+            // TRANS: Title for all public timeline pages but the first.
+            // TRANS: %d is the page number.
             return sprintf(_('Public timeline, page %d'), $this->page);
         } else {
+            // TRANS: Title for the first public timeline page.
             return _('Public timeline');
         }
     }
@@ -153,33 +155,38 @@ class PublicAction extends Action
      *
      * @return void
      */
-
     function getFeeds()
     {
         return array(new Feed(Feed::RSS1, common_local_url('publicrss'),
+                              // TRANS: Link description for public timeline feed.
                               _('Public Stream Feed (RSS 1.0)')),
                      new Feed(Feed::RSS2,
                               common_local_url('ApiTimelinePublic',
                                                array('format' => 'rss')),
+                              // TRANS: Link description for public timeline feed.
                               _('Public Stream Feed (RSS 2.0)')),
                      new Feed(Feed::ATOM,
                               common_local_url('ApiTimelinePublic',
                                                array('format' => 'atom')),
+                              // TRANS: Link description for public timeline feed.
                               _('Public Stream Feed (Atom)')));
     }
 
     function showEmptyList()
     {
+        // TRANS: Text displayed for public feed when there are no public notices.
         $message = _('This is the public timeline for %%site.name%% but no one has posted anything yet.') . ' ';
 
         if (common_logged_in()) {
+            // TRANS: Additional text displayed for public feed when there are no public notices for a logged in user.
             $message .= _('Be the first to post!');
         }
         else {
             if (! (common_config('site','closed') || common_config('site','inviteonly'))) {
+                // TRANS: Additional text displayed for public feed when there are no public notices for a not logged in user.
                 $message .= _('Why not [register an account](%%action.register%%) and be the first to post!');
             }
-	}
+        }
 
         $this->elementStart('div', 'guide');
         $this->raw(common_markup_to_html($message));
@@ -194,7 +201,6 @@ class PublicAction extends Action
      *
      * @return void
      */
-
     function showContent()
     {
         $nl = new ThreadedNoticeList($this->notice, $this);
@@ -224,11 +230,15 @@ class PublicAction extends Action
     function showAnonymousMessage()
     {
         if (! (common_config('site','closed') || common_config('site','inviteonly'))) {
+            // TRANS: Message for not logged in users at an invite-only site trying to view the public feed of notices.
+            // TRANS: This message contains Markdown links. Please mind the formatting.
             $m = _('This is %%site.name%%, a [micro-blogging](http://en.wikipedia.org/wiki/Micro-blogging) service ' .
                    'based on the Free Software [StatusNet](http://status.net/) tool. ' .
                    '[Join now](%%action.register%%) to share notices about yourself with friends, family, and colleagues! ' .
                    '([Read more](%%doc.help%%))');
         } else {
+            // TRANS: Message for not logged in users at a closed site trying to view the public feed of notices.
+            // TRANS: This message contains Markdown links. Please mind the formatting.
             $m = _('This is %%site.name%%, a [micro-blogging](http://en.wikipedia.org/wiki/Micro-blogging) service ' .
                    'based on the Free Software [StatusNet](http://status.net/) tool.');
         }
diff --git a/actions/publicxrds.php b/actions/publicxrds.php
index 8f0337e4f7..aac6f423cf 100644
--- a/actions/publicxrds.php
+++ b/actions/publicxrds.php
@@ -1,5 +1,4 @@
 <?php
-
 /**
  * Public XRDS for OpenID
  *