Will anonymous reviews be protected by the first amendment?

This morning’s local paper featured a story about a Tampa lawyer who is involved in legal action over an anonymous online review of her business. She claims that the reviewer was not one of her clients, and is just someone who is trying to ruin her professional reputation, by posting a false review about her on Avvo.com. She is hoping that a Seattle court will (among other things) oblige the review site to disclose the identity of the reviewer.  This is one to keep an eye on, since the ruling on this case may have implications for other sites which allow individuals to post online reviews anonymously.