I just saw the message that someone else got, I have yet to receive it. However, it does actually have an opt-out message at the bottom. The question is, what happens when you opt-out, do they take you off the list, or do they remove your forums account.
update: the guy who sent me the email has sent a reply to ask to be removed from the list, time to see what the response will be. hopefully it will be the right one.