Well, in the U.S., you, as the forum operator, are protected from liability for what your users post.  You are not liable if someone slanders someone else on your forum.  You aren't liable if someone posts material that infringes on copyright either.

But (and a big but), if you are notified that something is slander, infringes a copyright, etc., or if you knew it was there and a "reasonable person" would know that something posted was slander or infringes a copyright, etc. and you don't take it down, then you could become liable.

Also, it is possible that you get sued even if legally you are not liable under the law.

Also some countries, like the U.K., do not have the same protections.  Which really sucks considering that you could get fined for what someone else did.  I don't think that is fair and just, but that is the law in a lot of countries.

And disclaimers always help.  They are better than nothing, and do give your lawyer something to talk about.  You might even be able to sue them back for violating your terms and conditions!

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