It is many clients’ latest nightmare: An unhappy customer takes to the Internet, venting his or her complaint about the client’s product or service on any one of 50,000 Internet discussion groups, chat sessions or 600 million Web pages. There is a proliferation of Web sites aimed at gathering consumer complaints against a single company–such as the “U-Hell” site, devoted to horror stories involving U-Haul moving vans, and “,” a critique of United Airlines’ service.

The so-called sucks sites, such as “,” concerning Bally Total Fitness health clubs, are so popular that Bell Atlantic pre-emptively reserved the domain name to bar anyone else from using it.