--- taxonomy.org.module	2007-01-04 15:32:04.000000000 +0100
+++ taxonomy.module	2007-02-18 12:53:00.561037900 +0100
@@ -1143,6 +1143,8 @@ function taxonomy_render_nodes($result) 
     $output .= theme('pager', NULL, variable_get('default_nodes_main', 10), 0);
   }
   else {
+    // remove (outdated) terms without content from search engines
+    drupal_set_header('HTTP/1.0 404 Not Found');
     $output .= t('There are currently no posts in this category.');
   }
   return $output;