[Tony G]

This isn't more of a copyright issue but a contracual one..

If you had something like that in your T&C, yes those posts are yours but it does not mean by a long shot that they are copyrighted. You'd have to take further steps than that. The only legal right you have is that if those posts are used elsewhere without your permission, then you'd be able to sue for breach of contract. So don't get the two mixed up. There are different processes for both and definitely a lot of ways out being binded by a contract. But the way vBulletin do it - it would work in the legal world.

(Don't hold my word on this though, but I think I've got it right)