Looks ok, it's quite busy at the moment and has several interesting angles (some of which in their Wikipedia page). Do they have a chance? Erm... probably not. So many have come and gone. The main problem with Facebook is not features, it seems to me, but momentum and, most of all, reach. If you can persuade my sister in Venezuela, my cousins and old aunties in Italy, my friends in the four corners of the globe to switch away from Facebook I'll then believe you have a FB killer. In the meantime, it's just a little fun to play with.
In any event, I'm there at http://www.tsu.co/flaviomatani -you can set up an account starting on that link.