Index: sites/all/modules/addthis/addthis.module
===================================================================
--- sites/all/modules/addthis/addthis.module	(revision 16278)
+++ sites/all/modules/addthis/addthis.module	(working copy)
@@ -184,10 +184,10 @@
   global $_addthis_counter;
 
   // Fix IE's bug.
-  if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== FALSE) {
-    
+  static $fix_ie_bug = TRUE;
+  if ($fix_ie_bug && strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== FALSE) {
     $protocol = $_SERVER['HTTPS'] == 'on' ? 'https://' : 'http://';
-    
+    $fix_ie_bug = FALSE;
     drupal_add_link(array(
       'rel' => 'stylesheet',
       'type' => 'text/css',
@@ -230,7 +230,7 @@
         $_SERVER['HTTPS'] == 'on' ? 'https://secure.addthis.com' : 'http://s7.addthis.com',
         variable_get('addthis_widget_version', '152')
       );
-      $button .= '</script>';    
+      $button .= '</script>';
     }
   }
   return $button;