PhotoMost of us are happy to read a glowing movie review. It's probably a movie we'd like to see anyway, and we're grateful someone in authority – a reviewer – has blessed it and told us we'll like it.

Does the same hold true for products? Retailers and manufacturers are betting it does, and they too are happy to believe that. Instead of spending millions on a TV commercial to run during the Super Bowl, they use a fraction of their ad budget and offer incentives for consumers to post positive reviews on e-tailer sites like

Bing Liu, a computer science professor at the University of Illinois at Chicago, calls it “opinion spam.”

Opinion spam

“Opinion spamming refers to illegal activities that try to deliberately mislead readers or automated opinion mining and sentiment analysis systems by giving undeserving positive opinions to some target entities in order to promote the entities,” Liu said.

While a casual reader might not be able to easily spot a bought-and-paid-for review, Liu is working on software that will detect them. On his website, Liu shares some of the signals he looks for.

Spotting a phony review

For example, pay close attention to the review content. Can you detect content and style similarity among different reviewers. Companies paying reviewers often have a list of “review points” they want their reviewers to emphasize in a positive way.

Also, note the screen name used by the reviewer and note if they are active on a lot of sites. Once you have isolated an individual, look for inconsistencies. Do they refer to their husband in one review and their wife in another, for example?

 “We believe that as opinions on the Web are increasingly used in practice by consumers, organizations, and businesses for their decision making, opinion spam will get worse and also more sophisticated,” Liu said. “Detecting spam reviews or opinions will become more and more critical. The situation is already quite bad.”

Researchers at Cornell are also working on software that acts as a "lie detector for the Internet." They said the software, after scanning 800 Chicago hotel reviews, was able to highlight 90 percent of the bogus write-ups.

Regulators take notice of trend

The Federal Trade Commision (FTC), which has taken a few companies to task for rewarding consumers for hyping their products, says the practice of paying a consumer to write a positive review isn't illegal, but not disclosing it is.

Last March a company selling a popular series of guitar-lesson DVDs agreed to pay $250,000 to settle FTC charges that it deceptively advertised its products through online affiliate marketers who falsely posed as ordinary consumers or independent reviewers.

The FTC said the complaint against Nashville, Tennessee-based Legacy Learning Systems Inc. and its owner, Lester Gabriel Smith, is part of an effort to make sure that advertising to American consumers is truthful and not deceptive, whether the advertisements appear in traditional or newer forms of media.

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