All those unsubscribe messages I saw did not meet the required format - don't forget they are handled by a dumb computer program and not usually read by a human (eg a human might recognize unscribe as a form of unsubscribe but a computer won't). The usual cause of problems was, I think, default email setting (eg sending in HTML rather than plain text, signature lines).
I would be interested in what happed yesterday - the first request seemed ok, then some one responded forgetting that emails from rootsweb usually have no connection with most recipients (compounded by leaving on the 'auto notify request' in outlook (a silly thing to reply to as this also confirms your email address for spammers - mind you any one using Outlook has opened door to all forms of spam + spyware anyway) - then someone repeated all messages to board and it blew up