They probably didn't gain enough traction and network effect before Facebook started its efforts to expand. Just to put that into perspective: by 2010, VKontakt

They probably didn't gain enough traction and network effect before Facebook started its efforts to expand. Just to put that into perspective: by 2010, VKontakte had around 60M users and exceeded 100M by the end of the year. Meanwhile Facebook wasn't even fully translated into Russian, and it was this obscure thing some hipsters used as their secondary social network.