I bet Friendster slit their wrist by now and Xanga is hanging from a internet rafter.
AsianAvenue drove off a cliff. Not intentionally, mind you.
BlackPlanet will still be up and running but white men will be too scared of it and white women are never told about it.
MySpace is still the desperate whore looking for any dollar it can find.
Sadly social sites, for the hundreds there are, will all live now in the shadow of Facebook and if Facebook dies it is only because it took out the last of the social networks and will have no more reason to go on.