I'm all for new ways of doing things and giving people freedom of expression, but the thought of anonymous posting just doesn't sit right. I mean, for me, its who you are talking that's interesting. Anyone can post something that is sensational or provocative, but it is the context of the comment that makes it conversation worthy. For example, Stephen Hawking talking about the beginning of the universe, is much more interesting that Katie Price talking about the unifying theory [actually, thinking about it, that's probably not the best example.]
Anyway, I hope you get my point - social media for me is about the 'who' not the what.