(Data as of Feb 24, 2010)
Looking at the list of top social networks on AddThis (overall sharing, last 30 days) it's quickly apparent that while Facebook and MySpace dominate, at least half of the other top 12 services are destinations that are popular outside the United States. Orkut, Viadeo, Sonico, meinVZ, studiVZ and Hyves are all social networks that are very popular in other countries, and the others have heavy international usage as well.
A Closer Look at Orkut
Orkut is a great example; Wikipedia notes that although it started with a heavy US user base in 2004, by 2010 Orkut's users heavily skewed towards Brazil (47%) and India (38%) because of, among other factors, the dominance of Portuguese as the primary language of its users.
These numbers are mirrored by the sharing stats for Orkut via AddThis, where it's usage is heavily dominated by users in Brazil, India and Portugal.
If you compare the United States to Brazil, in the latter country Facebook is only #5 and Orkut enjoys over three times as much sharing:
Top 10 Services
GlobalWebIndex.net offers another interesting insight: while 43% of US internet users manage a social network profile, almost 60% of users in Brazil do, and these numbers persist across several other measures of online social activity. That's a heavily engaged and active social audience.
United States
(Screen grabs from GlobalWebIndex.net)
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