What social networks do you belong to? Personally I use Linkedin for business-related networking and Facebook for personal connecting.
I found a very interesting layout of social networking worldwide that shows MySpace and Facebook mostly ruling in the Americas with Orkut, Beebo and some others (a couple of which I was blissfully unaware of until now) having higher share elsewhere.

I have noticed Linkedin coming out with a few new features lately, perhaps we can persuade them to get a little more “Facebooky”, though they can certainly stop short of the Vampires Challenges and Sheep-tossing applications that seem to proliferate lately.
RossB