I heard about this on CNN today. Unfortunately for Microsoft, I don't think money can buy members and an active community the way they think it can. I personally don't like how they're going for more of a personal webpage kind of thing, from what I read. Many of the people that use social networking and blogging services aren't too into web design.
But we'll see what happens, I highly doubt it will get off the ground like they expect, then again, I'm not sure what audience they're targeting.