Thomas Crampton presents this interesting map of the dominant social networking services in Asia produced by Ogilvy.
What is most striking is the diversity. It confirms the view that most people use social networking to stay in touch with close friends, not to span the world. Interestingly people who migrate or have transnational families seem to take their Social networking service with them. I have interviewed people from Brasil where Orkut is dominant, living in Europe that use Orkut daily. It would be nice to have a map of these services in Europe and correlate it with maps of migrant communities.