What I see as the crucial part is the "social" component. I'm afraid this somewhat derails Alessandro's intended discussion as my point totally ignores "who" the current owner of github is. If you have a project and are looking for more developers to join it, you need some kind of visibility so potential developers get aware of you. In that sense, github serves as a social network and its current state is close to amazon or ebay - and that is what I suspect is why they even bothered to buy it.