​Bah humbug: How to spot fake online reviews

No one wants to find out they've been conned over the holidays. But some consumers may end up finding coal in their stockings, thanks to the season's blizzard of fake reviews.

Fake reviews came under the legal scrutiny of online retailer Amazon.com earlier this year when it sued more than 1,000 people it claimed were posting phony reviews for $5 a pop. It's not only an issue for Amazon. Sites ranging from eBay to TripAdvisor have faced consumer complaints about the issue. The problem is, even after the legal action, fake reviews continue to proliferate. Amazon didn't immediately return a request for comment.

There's more at stake than ever this holiday season, given that online shopping is forecast to jump 11 percent to $83 billion, according to a forecast from Adobe. Since consumers tend to rely on reviews to make purchasing decisions, that provides an incentive for unscrupulous business owners to pay a few bucks for fake reviews.

"There is a lot of money spent on low quality stuff" because of fake reviews, said Saoud Khalifah, a software developer and adjunct professor at Monmouth University who was inspired to develop a site called Fakespot after glowing reviews for a sleep supplement convinced him to buy it. After the supplement didn't work, he studied the reviews more closely and realized many were fake.

It's mostly smaller companies that are paying people -- or using bots -- to post phony reviews, Khalifah said. Having positive reviews helps products jump to the top of Amazon's top-seller lists, which can then lead to more sales. Skeptical consumers can put in a link to a product into Fakespot's site, which analyzes the reviews and determines the percentage of phony ratings.

The fake-review machine doesn't seem to be slowing down. Even a month after Amazon's lawsuit, dozens of listings on Fiverr offered to provide positive reviews for $5.

One reviewer on Fiverr promises to "post a positive review emphasizing all of the best parts of your book." The reviewer also provides a tip to avoid getting caught by Amazon: "Please do not send attachments OR links. Certain sites, especially Amazon, can trace these links and the review will be deleted."

"There is so much stuff out there that you can't even trust is real," said David VanAmburg, director of the American Customer Satisfaction Index. He said his company considered tracking online reviews as part of its measure of consumer experiences, but was put off by the high percentage of fake reviews.

"How do we trust that there aren't a lot of people working for a TV manufacturer to pump up the ratings? It becomes very sketchy to look at people giving ratings on merchant sites," he added.

It's not always easy to pick a fake, especially if they're well crafted, although there's no lack of them: As many as 20 percent of all Internet reviews are fake, according to NewYorker.com editor and CBS News contributor Nick Thompson.

Some consumers are fighting back, such as the Twitter campaign called #noreceiptnoreview, which is asking TripAdvisor to insist that reviewers post a photo of their receipt for restaurants and hotels before they can post a review.

Aside from actual proof that the reviewer is legit -- such as knowing the reviewer personally -- how can consumers pick out the fake reviews from the real ones?

There are a few tip offs, such as too-detailed comments that include the make-and-model number of the product, as well as exaggeration, according to this tip list from Coupon Sherpa. The timing of reviews can be a red flag, such as if there are multiple postings all within a short period of time.

But people aren't very good at spotting fake reviews, according to Cornell University researchers, who found that human judges were no better at picking out the fake reviews than someone choosing based on chance. They developed a dataset that could be used to detect fake reviews, and consumers can plug in suspect reviews at ReviewSkeptic.com. (It notes that it's best for hotel reviews written in English, and is for entertainment purposes only.)

The bottom line? As you browse online to shop for holiday gifts, look under the hood at product reviews, and keep a dose of skepticism at hand.