Index: modules/node/node.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/node/node.module,v
retrieving revision 1.858
diff -u -p -r1.858 node.module
--- modules/node/node.module	16 Jul 2007 12:43:05 -0000	1.858
+++ modules/node/node.module	18 Jul 2007 00:00:34 -0000
@@ -805,7 +805,7 @@ function node_prepare($node, $teaser = F
   // First we'll overwrite the existing node teaser and body with
   // the filtered copies! Then, we'll stick those into the content
   // array and set the read more flag if appropriate.
-  $node->readmore = (strlen($node->teaser) < strlen($node->body));
+  $node->readmore = $teaser && ($node->teaser !== '') && ($node->teaser !== $node->body); 
 
   if ($teaser == FALSE) {
     $node->body = check_markup($node->body, $node->format, FALSE);