Network Effect is a concept everyone in the Bitcoin world needs to read up on (specifically those in the alt coin world).
Nobody is killing Facebook anytime soon.
-B-
Yea, that's what Myspace thought, though I know you're going to say those can't be compared because Myspace wasn't even worth 1billion at the time and it didn't have the same dominance of the industry that FB has now and FB is worth more than a dozen billion, so the chance of another social network taking down FB is extremely slim because of the Network Effects(it's know by a large range of people, they've grown accustomed to using it, it has a large following, large funds, marketing, etc), but my response is: You're right, I just felt like adding in that.