Richard Bridge, you're right in what you implicitly stated in your post above--it's a tangle!

My own hunch is that the Mudcat can't rely on 17 USC 108. Section 107 will (in my own strictly private this-is-not-legal-advice-and-does-not-establish-a-lawyer/client-relationship opinion) cover some of what happens in the forum, but not necessarily everything. If someone posts an entire copyrighted lyric without any accompanying commentary or discussion, that might be over the line.

ISP liability for subscriber infringement is a hot topic. It's the subject of some recent legislation and some recent court cases. Max should probably consult a lawyer about on-line fair use. Not just any lawyer, but one with experience in on-line copyright issues. Then, if necessary, he can set up some guidelines for posting copyrighted material to the forum and ask the Mudcat to help keep the forum within the guidelines--which I think all of us will be glad to do.

T.