This seems like an easy problem to solve. Copyright covers the wording of the communication; it doesn't cover the ideas conveyed. Facts cannot be copyrighted. That means you can tell someone that didn't sign one of these contracts your experience with the dentist, and they can write it up on the review site for you. The dentist won't own that work and will have no grounds to claim that the author infringed his copyright.<p>By analogy, this is like saying "The Simpsons is a TV show about a guy named Homer." Although it would be illegal for me to give you a verbatim copy of every Simpsons episode, it's not illegal for me to tell you what happens in each.<p>A nondisclosure agreement might be more effective, but still wouldn't allow a bad review to be taken down by a DMCA claim. The dentist would have to go to a real court for that to happen, and I doubt a real court (or medical ethics board) would be too pleased about a contract prohibiting a patient to talk about his doctor.<p>Ironically, my orthodontist was considering a contract like this, but I talked some sense into him and it seems like he's not going to go through with it. And no, I wouldn't sign it; there are hundreds of other orthodontists in Chicago.