Caught red-handed, indeed. 

Online review site Yelp has outed nine small businesses for trying to solicit favorable reviews. Each of the businesses will now have a "consumer alert" badge placed on their Yelp page for 90 days, alerting users that "We caught someone red-handed trying to buy reviews for this business." 

Yelp, which posts consumer reviews of businesses, caught the companies trying to pay for positive reviews in a sting operation, according to a New York Times report. As part of their punishment, Yelp will also allow visitors to see the emails sent by the guilty companies trying to hire reviewers.

"For the businesses that are out there working really hard to establish a legitimate, stellar reputation; that are working around the clock to provide great services to their customers, they earn their four or five star reviews," Stephanie Ichinose, Yelp's director of communications, told Inc. "To have other companies taking a shortcut is not something we take lightly."

Ichinose added that Yelp will start making customers aware of when a large number of reviews are submitted from the same IP address, an indicator of review dishonesty.

The companies busted in the sting reportedly used Craiglist to try and find "elite" Yelpers--someone who regularly posts reviews on the site and is respected within the Yelp community--to post positive reviews of their busisnesses for money. For example, Bert Levi of Levi Family Jewelers in San Diego said he would pay $200 for a positive review of a new custom-designed ring. A pest control company offered $5 to post a prepared statement, while a moving company offered $50 for an "original" review. 

Yelp has long said that maintaining the integrity of its reviews database is paramount to its own business model and has used a review filter and, at times, manual oversight to ensure reviews are legitimate. According to the Times, internal filters hide approximately 20% reviews on the site.