Reminder: as of May 11, 2006, mail addressed to users at has been bouncing back to the sender with an informative message.  The host name is scheduled to be removed from the Domain Name System (DNS) on August 11.
Once the domain name is fully retired, e-mail sent to any address at will be rejected by the sender's e-mail system with a message that the sender is trying to send to an unknown host.
Please see for details.