This message is becoming an old friend:
This message was created automatically by mail delivery software. A message that you sent has not yet been delivered to one or more of its recipients after more than 2448 hours on the queue on [deleted].
[… cut info about message …]
No action is required on your part. Delivery attempts will continue for some time, and this warning may be repeated at intervals if the message remains undelivered. Eventually the mail delivery software will give up, and when that happens, the message will be returned to you.
Some spammer sent a message “from” Tad-razaherp@[my domain] to a bogus address at [deleted], and now [deleted] thinks it is doing me a favor by being so persistent. Every few days I get another notification, with the hours increased. Right now, at 2448 hours, the remote system has been trying to deliver “my” message for 102 days. I think that exceeds the recommendations in the RFC’s just a little. It brings a whole new perspective to “eventually […] will give up”.
Update 2010-02-19: Well, it’s been almost a month since my last reminder at 4560 hours (190 days). It looks like the remote server has finally given up.
image derived from: Joseph Barillari, Usps-van.jpg, Wikipedia