Quite an interesting visualization of the spread of social services in the world: In an interactive way you can play with it on the site Many Eyes . Visualization is based on Alexa and Google Analytics.
Top 3 social services by country:
Australia : Facebook, MySpace, Twitter
Canada : Facebook, MySpace, Flickr
India : Facebook, Orkut, Hi5
France : Facebook, Skyrock, MySpace,
China : QQ, Xiaonei, 51
Germany : Facebook, StudiVZ, MySpace
Italy : Facebook, Netlog, Badoo
Russia : V Kontakte, Odnoklassniki, LiveJournal
Spain : Facebook, Tuenti, Fotolog
United Kingdom : Facebook, Bebo, MySpace
United States : Facebook, MySpace, Twitter
The remaining finds can be read in the news from RWW . PS The following line looks funny: - V ( contact a lot like Facebook ) =)