Yelp has been hit with a second class-action lawsuit alleging that the review site aimed to "extort" companies by offering to hide bad reviews and promote positive ones in exchange for ad buys.

In the lawsuit, filed in federal district court in the central district of California, D'Ames Day Spa owner Christine LaPusky, alleges that Yelp removed 13 of 14 reviews of her business from the site after she refused to purchase advertising on the site.

Late last month, a veterinary center in California alleged that Yelp had offered to bury bad reviews in exchange for a $300-a-month ad buy.

Yelp CEO Jeremy Stoppelman denied any wrongdoing. "This suit, like the other, is without merit, we will fight it aggressively and we believe we will win," he wrote on the company blog.

Stoppelman added that LaPusky had solicited the reviews from her customers -- which, he said, made them more likely to be flagged as shill reviews by Yelp's filter. "If a business could garner a top rating on Yelp simply by soliciting 5-star reviews from friends, family, and favored customers, how useful would such a site be?" he wrote.

LaPusky doesn't dispute that she solicited reviews; she alleged in her lawsuit that she intentionally asked customers to leave feedback on Yelp. But she also alleged that initially, only three reviews were removed.

She asserts in her complaint that when she inquired about why those reviews were taken down, a marketing representative told her that the company analyzed posts for fraud. "LaPusky received no explanation of the criteria the 'automatic system' uses to find suspect comments," she alleges.

LaPusky also alleges that the marketing representative pushed her to purchase advertising on the site, but she declined. Several days later, a Yelp sales representative allegedly called LaPusky to again ask her to purchase ads. She alleges that she again declined, and shortly afterwards, Yelp removed the other 10 other reviews.

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