All of my daughters friends left MSN and went to Facebook, because the place was burning venture capital, and offering everything for free. Now, Facebook is attempting to pay their bills! Trying to squeeze money out of this bunch is hopeless! Their major purchasing power is to nag the parents into letting them have a cell phone, and they all have one. None of them actually buy anything, except clothes, and they don't put much effort into that!
I expect that Facebook will greatly annoy them, and they'll move to this new Google arrangement, which will be free for a year or two. Even Google is just living on the hopes and dreams of advertisers. I certainly can't squeeze any money out of my readers! :)