>the value in having the list processor sign all posts >is simple. guaranteed identification of the list >traffic for any recipient who decides to verify >signatures. This seems to solve a non-problem. Unless there are spam messages that where the sender has, for instance, forged the existing "Sender: owner-ietf@xxxxxxxx" header, signing these messages will add nothing of value. It seems much more likely that a spammer would simply send e-mail to the ietf@xxxxxxxx list & allow the list itself to propagate it than that they would specifically forge that header.