--- a/.emacs-my	Thu Aug 09 19:37:40 2012 +0300
+++ b/.emacs-my	Thu Aug 09 22:01:57 2012 +0300
@@ -1428,7 +1428,7 @@
 
 (defun gnus-user-format-function-d (header)
   (let ((time (gnus-group-timestamp gnus-tmp-group)))
-    (if time
+    (if (and time (time-less-p (time-subtract (current-time) time) (seconds-to-time (* 3600 24 7 30 2))))
         (format-time-string "%Y-%m-%d %H:%M" time)
       "")))