And who's to say that Orkut is even Google's response to Facebook. It was an acquisition, if anything I see it as a technology buy. They wanted to know how a social network would operate and function and they bought something that works in the International market to test it.
But I still think my point still stands, social networking is just a paradigm. It is not separate service or platform, it is just how features are organized. And almost every feature Facebook has, GYM has. The only innovation Facebook ever done was come out with poke. But then again, I've been pinging or yt?-ing my friends since AOL 2.1.