So Proboards officially told me that I don't have to remove shit from my site The official term is that I am "not obligated".

This comes about for several reasons.
--The contributer did so willingly, giving ideas to us freely.
--They are ideas, unlike tangible things such as an image, and so they can't be protected. Any member could claim to have come up with an idea, so it can't be proven that someone "thought of it first" xD
--The contributer had no formal copyright over them, like JK Rowling has on Harry Potter or anything.

So my site can't be deleted for that and I don't have to do anything. It isn't stealing and I can laugh about this later.

Or now.