If you are talking about VKontakte in Russia, you are wrong. VKontakte (launched 2006) is a clone of Facebook (even the design is copied from FB). It's criticized in Russia for the same reasons as FB here.
FB lost because VK was specifically targeted at Russian audience from the beginning.
Well, I can say that they've copied older version of facebook and it seems more convenient for some people. Also do not forget audio and video sharing applications. It is like Napster since it allows users to exchange their collections.
FB lost because VK was specifically targeted at Russian audience from the beginning.