Yeah that's definitely not what I meant or what the presenter seems to be implying. If it helps spam scores even a little bit, that's very interesting and potentially worth implementing in private hosts that often get dinged by larger hosts just for not being well-known. It doesn't need to get anywhere near turning actual spam into non-spam.
Why not? Spammers do. I get spam to my gmail all the time.
Sign up for a google apps account and send outbound cold sales spam via gmail. Seems to work exceedingly well judging by my inbox.
By that you mean 2003 was the first year this vulnerability was reported to you, and every year since you've been auto-replying "nothing to see here" when people kept reporting this vulnerability to you?