See these two examples :
http://www.facebook.com/login.php?next=http%3A%2F%2Fwww.face...
inurl:bcode=[]+n_m=[] site:facebook.com
Goes to some Obama site and redirects to another page. However, using it a second time results in Firefox reporting that it doesn't understand the URL.
See these two examples :
http://www.facebook.com/login.php?next=http%3A%2F%2Fwww.face...
http://www.facebook.com/login.php?next=http%3A%2F%2Fwww.face...