A diverse group of businesses have joined in a class-action suit brought against Yelp for aggressive ad sales that the plaintiffs say amount to extortion. Yelp has made some changes to its features in an attempt to "clarify" how advertising affects a business listed on the site, though lawyers for the plaintiffs say that it doesn't directly address the practices that led to the lawsuit.

In February, a veterinary hospital in Long Beach, California accused Yelp of attempting to extort expensive advertising contracts from the company in exchange for removing false reviews left for the company on Yelp. Lawyers for the hospital filed a federal class-action lawsuit in California after discovering that numerous other businesses had recounted similar problems in articles published last year in the Chicago Tribune, the Wall Street Journal, and in particular the East Bay Express.

Yelp's terms of service forbid leaving reviews with false information, but businesses have had little success in getting such reviews removed. Instead, Yelp relies on a secret filter ostensibly meant to identify both positive and negative reviews that are left in bad faith, e.g., reviews left by employees of the business to raise ratings, or negative reviews left by people that haven't even visited the business.

In March, lawyers in the case filed an amended complaint after nine other businesses joined as plaintiffs, all citing specific instances of Yelp ad sales representatives making repeated attempts to sell ad contracts. Ad representatives promised positive reviews from "Yelp Elites"—heavy users of the site with favored status—in exchange for advertising, or threatened negative reviews from Yelp Elites if they did not. Many businesses experienced negative reviews that often contained false information or personal attacks on business owners after declining to advertise. Such reviews violate Yelp's terms of service, as previously mentioned, but were not removed.

Today, Yelp told The New York Times that it was making some changes to its website to address the numerous complaints from small businesses. It will no longer let businesses that advertise on Yelp choose a review to "highlight" by always making it appear first. It will also allow users to click a link and read reviews that have been "filtered" by Yelp's secret algorithm, though those reviews won't affect a business' overall rating.

"I hope that these changes will debunk some of the myths and conspiracy theories out there about Yelp and its advertising and whether those are linked," Jeremy Stoppelman, cofounder and CEO of Yelp, told NYT. Stoppelman has long maintained that the problem isn't Yelp, but merely confusion on the part of business owners that rely on positive Yelp feedback to keep customers coming through the door. "It will underscore the point that it really is and has always been a level playing field for businesses, and will showcase the unique challenge we face, in certain situations where it's obvious businesses are trying to change ratings," he said.

These changes are a good first step, but don't go far enough according to the lawyers that represent the plaintiffs. "Small businesses have been expressing their outrage at Yelp’s dirty business practices for a long time, and it is unfortunate that it took the filing of a class action to get Yelp to make even these amends," attorney Jared Beck said in a statement.

"It doesn't really address the concerns brought up in the lawsuit—that Yelp effectively extorts money from businesses by threatening negative reviews if they don't pay for advertising on the site," attorney Greg Westin told Ars.

We attempted to contact some of the businesses cited in the lawsuit for comment, but none wanted to go on the record, citing threats and harassment for participating in the suit. Other business owners Ars spoke to confirmed being on the receiving end of the actions described in the lawsuit.

Yelp is a helpful site when trying to find a good restaurant or store to try, especially if you are just visiting or are new to an area. But its usefulness depends on whether or not you can trust the reviews and ratings left by its users. If the reviews are being manipulated to encourage business owners to buy advertising, the trust relationship is broken. Users, businesses, and Yelp alike could all benefit from more transparency in how Yelp's filtering works and how ratings are displayed on a business' page.