BOSTON » The hotel review might sound too good — citing obscure details like the type of faucets — or perhaps one stands out as the only negative rating of an otherwise popular location.

The influential travel Web site TripAdvisor has been quietly posting disclaimers to warn customers of hotels writing fake reviews to improve their popularity rankings or hurt competitors.

The red disclaimers near the names of hotels show that TripAdvisor has a problem with fake reviews, travel bloggers and industry experts say. One blogger, Jeff Tucker, warned that without changes to restore credibility to the reviews the site is “;going to come crumbling down behind them.”;

But TripAdvisor said the disclaimers have been used since 2006 and involve a small fraction of the 400,000 hotels reviewed. The company, based in Newton, Mass., said it has a successful system to root out inaccurate reviews.

“;The 23 million reviews and opinions are authentic and they're unbiased and they're from real users,”; spokesman Brooke Ferencsik said. “;The vast majority of hoteliers, they understand the risk to their business and reputation if they attempt to post fraudulent information to TripAdvisor.”;

The problem of policing online reviews is not limited to TripAdvisor:

» Last fall, Apple required that consumers purchase or download an application before they can review it online in the App Store.

» A plastic surgery company, Lifestyle Lift Inc., agreed to pay $300,000 to resolve an investigation into positive online reviews written by employees, the New York attorney general announced Tuesday.

» And the Federal Trade Commission is revising guidelines on testimonials and endorsements to reflect the growth of online marketing.

TripAdvisor, which is part of Expedia Inc., was the third most popular travel information site in June, with about 9.2 million unique visitors, according to the tracking firm comScore.

The company ranks hotels according to how well they have been reviewed, and loyal users say it is the best place to find accommodations, from ritzy resorts in major cities to mom-and-pop inns far off the beaten path. Users are directed to other sites such as Expedia to book rooms.

But last month travel Web sites and blogs began to log and discuss the red warnings, which read: “;TripAdvisor has reasonable cause to believe that either this property or individuals associated with the property may have attempted to manipulate our popularity index by interfering with the unbiased nature of our reviews. Please take this into consideration when researching your travel plans.”;

One industry Web site, BeatOfHawaii.com, said it found 92 hotels with the label in June, from a boutique hotel in Hawaii to a Radisson in Fort Worth, Texas. The disclaimers drew a lot of attention that month and by Monday, only 16 remained, said Tucker, co-author of BeatofHawaii.com.

The disclaimers have an expiration date that varies with each hotel, Ferencsik said. He said TripAdvisor works with hotel owners to get the warnings removed, often after they promise to stop breaking the site's rules.

“;Not only does it give our travelers fair warning,”; he said. “;But also it should be a deterrent for any property that's thinking about trying to game the system.”;