At its core, I don't view Facebook as a social network. I think it could become the driver's license of the Internet. And beyond that, it can become the pipes and the plumbing upon what most of the Internet is built. I think it's very well positioned.

In all cases where doubt crops up, ask yourself, "If I had a gun to my head and had to do it, how would I do it?" It's not as hard as you think.