I have account on Facebook, Tweeter, My Space, Linked In, Google plus and Hi5. Mostly I'm updated on Facebook and Tweeter with my social network friends regularly.
for personal use, i use facebook and paltalk. But for business i have many social accounts like stumbleupon digg twitter etc.
I dont belong to any and i find my life to be more productive and im also not depressed anymore..... interesting maybe i should look into that more.
I used to be on Myspace and Bebo but deactivated them as I didn't use them. Now I'm fond of Facebook, Tumblr and Twitter and Blogger, if you class it as social networking.
I use more than 100 site like Facebook, Delilcios, Stamble Upon, Technorati, Orkut, Newsvine, Ezine, Google Plus, Reddit, Mysite, MySpace and etc etc.