On Wed, 25 Jan 2012 20:19:03 -0500, Austin Clements <amdragon@MIT.EDU> wrote: > One very common cause of this is someone using "reply" to get an > initial set of recipients, but then replacing the entire message and > subject (presumably without realizing that the mail is still tracking > what it was a reply to). This can also happen if someone > intentionally replies to multiple messages (though few mail clients > support this), or if there was a message ID collision. This is a very common occurrence for me as well. I would put money down that this is what you're seeing. jamie.