(CNN) -- Phrases such as "reviews you can trust" and "reviews from real travelers" have misled TripAdvisor users in the United Kingdom, according to a judgment issued Wednesday by the Advertising Standards Authority in Britain.
The decision comes in response to a complaint filed by a reputation management firm and two hotels, claiming that some of the claims of trustworthiness and authenticity on the very popular user-generated review site are misleading and can't be substantiated, since the site doesn't verify reviews.
"We told TripAdvisor not to claim or imply that all the reviews that appeared on the website were from real travelers, or were honest, real or trusted," the ASA wrote in its decision.
The issue is overblown, TripAdvisor indicates in its response to the ruling, saying the requested changes have already been made to the marketing copy on its website.
"We have confidence that the 50 million users who come to our site every month trust the reviews they read on TripAdvisor, which is why they keep coming back to us in increasingly larger numbers to plan and have the perfect trip," the company said in a statement, noting that the ASA's "highly technical view" relates to two marketing phrases used "in limited capacity."
The ASA's decision affects only TripAdvisor's operations in the United Kingdom, where the company has been under pressure from businesses that say some of the site's reviews are fake or defamatory.
Chris Emmins, co-founder of KwikChex, the reputation management company that filed the complaint, said it receives regular inquiries and complaints from hoteliers who say that false TripAdvisor reviews are hurting their business.
Unsubstantiated claims of bed bugs or food poisoning follow properties in online search results, and negative reviews are particularly damaging to small businesses since they don't receive a high volume of reviews and negative accounts tend to linger longer near the top of a company's listing, Emmins said.
TripAdvisor's claims of trustworthiness are misleading, he said.
"Patently, that just can't be true when you don't verify the fact that it's even a customer making the comments," he said.
TripAdvisor has changed course recently, replacing a "Reviews you can trust" tagline last year with "Reviews from our community."
"As with all marketing messaging, the wording used on the TripAdvisor site is constantly evolving to reflect different aspects of the business, which was the rationale behind a change back in June 2011 to put more focus on the TripAdvisor community," the company said.
While TripAdvisor doesn't claim to be 100% free of fraud, according to the ASA ruling, the company told the ASA it uses advanced fraud detection systems and substantial resources to combat fraud.
Emmins said it needs to do more.
"They could easily, with their resources, put in a tiered system which says 'this review has been authenticated,' " he said.
TripAdvisor points out that as a reputation management company, KwikChex has "an obvious commercial interest in undermining people's confidence in user content-generated review platforms."
The question of verifying reviews is far from resolved. In addition to damaging negative reviews, false positive reviews are used by some companies to bolster their rankings on review sites.
KwikChex has filed complaints with the Federal Trade Commission in the U.S., Emmins said. The agency said it could not comment on individual complaints.
Verified reviews or not, TripAdvisor's community is growing.
"It is very much business as usual," TripAdvisor said in its response to the ASA ruling.
"TripAdvisor was founded on a core set of principles -- to give travelers a voice to share their experiences, promote consumer choice and encourage a level playing field for everyone in the industry -- all within a free forum for sharing open and honest opinions."