Previously, we had Yuwie.com, but it doesn't exist now - it was shut down in 2011. Now, I prefer to focus my social network efforts on Twitter, Facebook and Google+. My next steps will be Tumblr, FriendFeed and, maybe, myLot.
I'm not sure if it's good to focus on SocialBook for marketing purposes. It looks like just a Facebook plagiarized. That's all.