According to a lawsuit filed last week in a California court, Yelp is suing the operators of Yelp Director, a company that also does business under the names Revpley and Revleap. Yelp claims Yelp Director undermines its integrity by allowing restaurants to post fake positive reviews and bury negative ones. As Consumerist points out, Yelp accuses the company of "trademark infringement, unfair competition, cybersquatting, contract interference" and a "state-level claim of false advertising."

Yelp first discovered Yelp Director in November of 2013 and sent the company a cease and desist order, but Yelp Director never complied. The lawsuit includes an email Yelp Director sent to potential clients:

Hi there,

We invented a software that allows you to proactively generate a large number of 4 and 5 star reviews from your customers in a way that makes them stick to the front page of Yelp. All reviews 3 star and below are filtered by the system and never posted online.

As CBS News points out, it's unclear if Yelp Director was ever successful in actually getting these fake reviews to "stick" to Yelp's pages. In a blog post, Yelp called Yelp Director a "scam" that could "put small businesses at risk" by charging for artificial inflation.

Last September, a California court ruled that Yelp had the legal authority to manipulate ratings and remove positive reviews from its pages, which means Yelp is just as likely to mislead its users as anyone else.