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 [...]

Twitter links are mostly in short URL format and you never know what you are clicking until you see the opened site. It is always better to click links from only trusted contacts.
Kaspersky folks are reporting that malware is making its way to twitter, Twitter, so be cautious with suspicious profiles and links. Some [...]