The Next Web has a great article on the domination of Facebook on all social network
An impressive number is the growth in Asia. Asia with its 278 million users beats Europe (251 million).
The top 5 social networks worldwide are: Facebook, QZone, V Kontakte, Odnoklassniki, and Cloob.
Link to the original article: http://thenextweb.com/facebook/2013/01/02/world-map-of-top-social-networks-shows-just-five-left-facebook-dominates-127-out-of-137-countries/