Royal Pingdom has some analysis on most searched social networks in various countries using Google Insights. The analysis is based on keywords, so it doesn’t actually tell the popularity of a social network in a country, as search volume doesn’t correlate well with the usage of the site.
The analysis shows some interesting results.

Facebook is [...]

Orkut has added a useful feature in India and Brazil that allows you to send orkut scraps via SMS from your mobile phone. Using this feature you can receive SMS notifications or send scraps to your friends.
This may not be available to all the users, if this feature is enabled for you, you will [...]