Good video here I watched it last year, I mean the concept is savvy imo for those forum owners who can't do for themselves however if you have a large forum that is already well ranked, is it worth it to give up so much revenue from ads and such? That's the main question for many because some want what they have already worked hard for! Now from my understanding, they won't go doing this for just any forum, you must also have a forum that benefits their network per say.
http://www.youtube.com/watch?v=LNgtlO9Ixt0