I can see what FB does right - identity and other apis are good, but the site itself has very poor usability, unfortunately. Author's point - that you usually have no idea where your message goes and who can see it - is one thing that makes me limit it's usage to a minimum.

And the very valid observation that FB wall is usually cluttered with senseless status updates and stupid game events from an otherwise intelligent people does not add any points, too.

But surely, seeing how well FB is doing for other people who don't want to learn all that complicated things to post pictures online, I give them credit. Just not 50B of it :)

FB will never become the new Internet, and probably will never even become Internet's identity DB. See interviews with Mark where he tries to reply to a direct question whether or not he understands what kind of responsibility he gets with owning 500mil user records. He has no idea. I foresee a horrendous crash of trust. Hope I'm wrong.