I still don't see it as a scam. If the terms of service didn't state that "all your data are belong to us", I might have been inclined to agree with your. But it is, afaik. And the site is a valuable resource for me, unlike things that I would classify as scams (like the "click here to see party pictures of your friends!" MSN spam worms).
And yes, I do feel that facebook is pretty harmless, since I choose which information I want to enter. So, they know my name and email address, and some of the people I know. Big deal. Of course there's a lot of sheeple who enter a lot more information about themselves, have compromising pictures, and install whatever spam-infested data-mining third-party "applications", but well... I'm not one of them.