Allan Martinson, a former Journalist, adds a lot of insight from his work as VC about Social Media and Social Software in the Baltic States, in Russia and others countries.
e.g. about Social Networks
Leading Social Network in Estonian: rate.ee
and for the Baltic Russians they have limpa.ru
Latvia's Social Networks draugiem.lv and one.lv
Lithuania's leading Social Network one.lt
Hungary's leading Social Network iwiw.hu
Multiple Russian social networks
odnoklassniki.ru (means classmates)
moikrug.ru (a Russian LinkedIn)
- not to forget Russian livejournal.ru (see Citizen Journalism in Russia)
(and I might add: vkontakte.ru - a Russian Facebook clone)
more / the Allan Martinson Interwiev
This information also adds valuable data to Nick Denton World Map of Social Networks