Two UK Web sites have been forced to identify a user who has been accused by a third Net company of posting defamatory messages.

Financial Web sites, Motley Fool and Interactive Investor International must out the user known only as "Zeddust" in an action brought by Net company Totalise. Both Web sites initially refused to reveal Zeddust's true identity.

The comments that defamed Totalise first appeared on Motley Fool's Web site and reappeared on Interactive Investor International's site. The comments were scrubbed and Zeddust banned from using both sites' chatroom.

Totalise now plans to sue for libel. The case could set a precedent for Web sites that allow the anonymous posting of messages.