For what? For communication, dating, education, learning language or what? The most popular russian social network: vkontakte.ru (as facebook), odnoklassniki.ru, my.mail.ru

Hi there Robert, Italki hs lots of resources for learning Russian http://www.italki.com/learn-russian/en-us

You can also try this free app with effective method of memorizing new words: https://play.google.com/store/apps/details?id=me.devinco.smarteach.ru

Listen-russian.com - site where you can learn Russian. Without registration and without advertising.

I recommend https://www.penpaland.com language exchange based website which allows to members learn/teach russian or any other language. Android app:http://app.appsgeyser.com/Penpaland