An ugly attorney-client fight in San Francisco Superior Court could help clarify how far clients can go in maligning their lawyers on consumer-review sites.

William Gwire, a prominent S.F. legal malpractice attorney, says hedge fund manager Elliot Blumberg defamed him with posts on complaintsboard.com. In the posts, Blumberg accused Gwire of a “horrific fraud” that ruined his life during the course of a legal malpractice action against Blumberg’s previous attorney.