I’m on a Yahoo Group with a couple other junior investment guys at VC firms around the city.  A message was sent to the list, which triggered an email to the entire group.  But, one of the group members has an vacation auto-responder setup to respond to every message that comes into his inbox.  So, everytime his auto-responder emails the group, it then triggers another group email, which in turn triggers an email from his auto-responder again.  It’s an infinite loop.