Heh heh. I guess you guys don't read Terms of Use, much? This is standard.
Virtually any website that you can upload content to has these terms - Facebook, Google, hell, Couchsurfing - every website I've ever signed up to and read the terms of us for (Blogger is another...and on).
That is: A) You own and are responsible for everything you post, but...
B) By posting it, you give them a license to do whatever the hell they want with it.
It's really the best for them, as if they "owned" it they'd have to take responsibility for it (or at least that's how things *should* work...). From reading Facebook's updated/clarified policy, when you take down an image/note/whatever, you end their license to use it.
Apparently they may save a copy anyway, but they don't have a right to use it then.
From what I understand.