I think, creating a social network, that is "a place where a person can chat with friends, share some photos and play a few stuipid games", is not a rocket science. No big deal. But in the 21st century that task becomes crazy impossible because of lots of "modern" "designers" doing their best in developing "new" "user" "experience".
I do not want to watch that cryptic postmodern art which is called Facebook for some reason. I just want to share dumned photos.
So yes... maybe Durov copied and pasted all the way. But that fact is VK remains usable and FB does not.