TripAdvisor, the influential web site that many travelers refer to as their Bible for hotel, restaurant and other travel reviews, may have a credibility problem. The American company was fined $610,000 by Italian regulators on Monday for failing to prevent false reviews on its site. According to the Italian Competition Authority, negative reviews on the site may have been made by people who did not actually visit the hotels and restaurants in question.

TripAdvisor is firing back. In an email statement, the company said, “We are reviewing the ICA’s decision, however from our initial review of the document, we think the ruling is unreasonable, strongly disagree with its findings and will file an appeal. We firmly believe that TripAdvisor is a force for good – both for consumers and the hospitality industry.”

Regardless of whether TripAdvisor’s Italian legal troubles are legitimate, the question of suspicious online reviews isn’t a new one. Researchers at Harvard University and Boston University found that nearly 20 percent of Yelp reviews are fake, while others at the University of Illinois concluded that 30 percent of online reviews are probably bogus. Of course, that doesn’t stop consumers from treating them as gospel: In a recent survey, 88 percent of consumers said they trusted online reviews as much as personal recommendation.

When it comes to travel, that misplaced trust can cost you serious money as you base your decisions about far-flung hotels and locations on the words strangers leave on a web site. But that doesn’t mean you have to be duped. Experts say there are several ways to sniff out fake reviews from authentic ones. Look for the following tells:

Hotel reviews that emphasize activities and family information rather than the hotels themselves. A study at Cornell University developed ways to sniff out plagiarism and falsehoods in reviews. Fake reviews were more likely to include information about fun and activities the place offers, while real reviews spent more time on details about the hotel. Researchers said it was a way for reviewers to sound relatable and personable.

Excessively emotional words and superlatives. According to a Bing Liu, a computer scientist at the University of Illinois, fake reviews are often way over the top. If you’re reading a description that describes something not just as good or reasonable but as the best thing ever, there’s a good chance it’s not based in reality. Cornell researchers agreed. “Deceptive writing often contains exaggerated language,” they wrote.

Overuse of certain key words. Liu also found that fake hotel reviews often featured words such as “us,” “price,” “stay,” “feel,” “nice,” “deal,” and “comfort.” The false restaurant reviews included words such as “options,” “went,” “seat,” “helpful,” “overall,” “serve,” and “amount.”

Reviews from people who don’t review anything else. Be suspicious if a reviewer only offers an extremely favorable or negative opinion about just one thing. Authentic reviewers are more likely to leave their opinions on a range of products.

Repeated use of the words “I” and “me.” The Cornell researchers found that fake reviewers emphasized using personal pronouns in order to seem more trustworthy. Because they haven’t actually experienced the place or product they’re reviewing, they overcompensate by saying things like “I ate the amazing risotto” rather than just saying “the risotto was delicious.”

Still not sure whether a review is real? Run it through Cornell’s “Review Skeptic” software, available for free online.