Index: includes/OutputPage.php
===================================================================
--- includes/OutputPage.php	(revision 21427)
+++ includes/OutputPage.php	(working copy)
@@ -745,8 +745,14 @@
 		$link = '[[' . $wgContLang->getNsText( NS_USER ) . ":{$name}|{$name}]]";
 
 		$blockid = $wgUser->mBlock->mId;
+		
+		if ( $wgUser->mBlock->mAuto ) {
+			$msg = 'autoblockedtext';
+		} else {
+			$msg = 'blockedtext';
+		}
 
-		$this->addWikiText( wfMsg( 'blockedtext', $link, $reason, $ip, $name, $blockid ) );
+		$this->addWikiText( wfMsg( $msg, $link, $reason, $ip, $name, $blockid ) );
 		
 		# Don't auto-return to special pages
 		if( $return ) {
Index: languages/messages/MessagesEn.php
===================================================================
--- languages/messages/MessagesEn.php	(revision 21427)
+++ languages/messages/MessagesEn.php	(working copy)
@@ -940,6 +940,13 @@
 You can contact $1 or another [[{{MediaWiki:grouppage-sysop}}|administrator]] to discuss the block.
 You cannot use the 'email this user' feature unless a valid email address is specified in your
 [[Special:Preferences|account preferences]]. Your current IP address is $3, and the block ID is #$5. Please include either or both of these in any queries.",
+'autoblockedtext'   => 'Your IP address has been automatically blocked because it was used by another user, who was blocked by $1.
+The reason given is this:<br />\'\'$2\'\'<br />You may contact $1 or one of the other
+[[{{ns:project}}:Administrators|administrators]] to discuss the block.
+
+Note that you may not use the "e-mail this user" feature unless you have a valid e-mail address registered in your [[Special:Preferences|user preferences]].
+
+Your block ID is $5. Please include this ID in any queries you make.',
 'blockedoriginalsource' => "The source of '''$1''' is shown below:",
 'blockededitsource' => "The text of '''your edits''' to '''$1''' is shown below:",
 'whitelistedittitle' => 'Login required to edit',