If you are one of the millions of travelers who have used TripAdvisor.com to check out the reputation of a hotel, you know many of its anonymous customer reviews are highly critical.

Just take a look. They're easy to find. These are real:

•"Could not sleep at night due to the sewage smells emanating from the bathroom ..."

•"There were spiders in the bathroom. The weekend reservations guy, Manuel, was not nice ..."

•"Had the lobster and got the most severe case of food poisoning I have ever encountered ..."

Now, a British reputation management company, KwikChex, is gathering unhappy hotel owners and travel providers in a group to fight back. It's threatening to file class action suits in Britain and the United States for defamation and libel unless TripAdvisor changes its policies.

TripAdvisor won't comment on "threatened or pending litigation," says spokeswoman Amalie Hurst.

The KwikChex group wants TripAdvisor to remove reviews that aren't verified but make serious charges such as crime, injury or illness. It wants other unverified insulting reviews taken down. Or else.

If you use TripAdvisor at all, you know two reviews of a property aren't enough to help you make a judgment, but 50 reviews of a property appear to be pretty accurate - after you eliminate the glowing ones obviously written by the manager's mother or the nasty ones obviously written by angry ex-bartenders.

The site has a team that scours the reviews to get rid of fake or questionable entries.

The problem for TripAdvisor is its repeated use of edited reviews to generate "Worst" lists. That seems to put them legally at risk because if they are creating these lists based simply on bad reader reviews, how do they take ownership for the ranking they know can destroy someone's business?

On the other hand, I am certain the advent of online reader review databases pressured hotels to improve. Everyone can use feedback. Everyone can get better. And managers don't always realize that while visitor opinions might sting, they can help make properties top-notch.

TripAdvisor is owned by the mega company Expedia. That means it has plenty of money to fight any suits that come its way. But the KwickChex group reportedly signed up a whole bunch of peeved travel providers who can make a lot of noise and trouble for the company if they are determined to.

In a perfect world, of course, anonymous reviews such as those on TripAdvisor are honest, true and insightful. They help travelers. They reward the best travel providers.

The problem is, the world is not perfect. On TripAdvisor, just as elsewhere on the Web, fakery, fraud and free-wheeling hostility can be spewed by anyone with five minutes and an ax to grind.

One interesting angle? As part of its anti TripAdvisor strategy, KwikChex might attempt to identify individual negative posters and go after them legally.

Stay tuned.