diff --git a/TODO b/TODO
index 7cc39f8459..8b3fe5b75f 100644
--- a/TODO
+++ b/TODO
@@ -13,7 +13,8 @@
 + subscribe links on profile
 + header menu
 + footer menu
-- disallow direct to PHP files
++ disallow direct to PHP files
+- require valid nicknames
 - common_local_url()
 - configuration system ($config)
 - RSS 1.0 feeds of a user's notices
diff --git a/action.php b/action.php
index 539077bc3f..ed25ac9d82 100644
--- a/action.php
+++ b/action.php
@@ -1,5 +1,7 @@
 <?php
 
+if (!defined('MICROBLOG')) { exit(1) }
+
 class Action { // lawsuit
 
 	var $args;
diff --git a/actions/settings.php b/actions/settings.php
index 826770ad7b..b2106ec396 100644
--- a/actions/settings.php
+++ b/actions/settings.php
@@ -31,4 +31,3 @@ class SettingsAction extends Action {
 		} else {
 			$this->show_form();
 		}
-				
\ No newline at end of file
diff --git a/classes/Notice.php b/classes/Notice.php
index f990675fba..a25afce2b9 100644
--- a/classes/Notice.php
+++ b/classes/Notice.php
@@ -1,4 +1,7 @@
 <?php
+
+if (!defined('MICROBLOG')) { exit(1) }
+
 /**
  * Table Definition for notice
  */
diff --git a/classes/Profile.php b/classes/Profile.php
index be4708a557..d6535238ac 100644
--- a/classes/Profile.php
+++ b/classes/Profile.php
@@ -1,4 +1,5 @@
 <?php
+if (!defined('MICROBLOG')) { exit(1) }
 /**
  * Table Definition for profile
  */
diff --git a/classes/Remote_profile.php b/classes/Remote_profile.php
index 6914bc2fbd..dde2b39aa3 100644
--- a/classes/Remote_profile.php
+++ b/classes/Remote_profile.php
@@ -1,4 +1,5 @@
 <?php
+if (!defined('MICROBLOG')) { exit(1) }
 /**
  * Table Definition for remote_profile
  */
diff --git a/classes/Subscription.php b/classes/Subscription.php
index 93b46b6f88..7d1881a321 100644
--- a/classes/Subscription.php
+++ b/classes/Subscription.php
@@ -1,4 +1,5 @@
 <?php
+if (!defined('MICROBLOG')) { exit(1) }
 /**
  * Table Definition for subscription
  */
diff --git a/classes/User.php b/classes/User.php
index 8234e07848..76f7da989f 100644
--- a/classes/User.php
+++ b/classes/User.php
@@ -1,4 +1,5 @@
 <?php
+if (!defined('MICROBLOG')) { exit(1) }
 /**
  * Table Definition for user
  */
diff --git a/common.php b/common.php
index 3a5278e494..973b1c6e6c 100644
--- a/common.php
+++ b/common.php
@@ -1,5 +1,7 @@
 <?php
 
+if (!defined('MICROBLOG')) { exit(1) }
+
 # global configuration object
 
 // default configuration, overwritten in config.php
diff --git a/config.php b/config.php
index c178baf9c9..cd00072a6f 100644
--- a/config.php
+++ b/config.php
@@ -1,5 +1,7 @@
 <?php
 
+if (!defined('MICROBLOG')) { exit(1) }
+
 $dsn = array(
 			     'phptype'  => 'pgsql',
 			     'username' => 'someuser',
diff --git a/index.php b/index.php
index 7237c08bc0..ee17b73d0a 100644
--- a/index.php
+++ b/index.php
@@ -1,6 +1,7 @@
 <?php
 
 define('INSTALLDIR', dirname(__FILE__));
+define('MICROBLOG', true);
 
 require_once(INSTALLDIR . "/common.php");
 
diff --git a/stream.php b/stream.php
index d30ee013c4..9f972d75e4 100644
--- a/stream.php
+++ b/stream.php
@@ -1,5 +1,7 @@
 <?php
 
+if (!defined('MICROBLOG')) { exit(1) }
+
 define('NOTICES_PER_PAGE', 20);
 
 class StreamAction extends Action {