I applaud this idea, but once you've joined how do you get your friends to follow you? Every so often I get emails like: "Bob invites you to join AwesomeSocialNetwork, click here to join!" and I totally ignore them.
I also wonder if the age of The Social Network is over. If a new better Facebook did come along, people wouldn't join it because deep down they all know that social networking is massive waste of time and will always end up being an endless stream of garbage. The only reason they've not all left Facebook yet, is fear of missing out.