3. Gotta reread that.
6. Oh come on, facebook, youporn, whatever. As I said, too vague.
Yeah, so he didn't call out a specific "type" of socializing, or draw up the wireframe for facebook here. But he just recognized there is a huge trend of people wanting to share their lives and communicate in near real time. I think he nailed it. Facebook and twiiter are just that. Even look at his move example. These days, you watch you movie or TV show, then laugh and comment on it with your friends not in the theater, but on facebook or twitter. I'd say he NAILED that prediction.
Git is open source.
That being said, GitHub does indeed match the description, though I think people are thinking about the code they are hosting for other people ... but I think where they fit the description is with the fact that they are hosting Git for you (and making some money through enterprise services).
3. He's not talking about using multiple cores, he's talking about using multiple threads vs (for example) multiple processes.
6. Reddit, Hacker News