Yelp has been hit with its third lawsuit in a few weeks. This time, it's a San Francisco furniture company basically accusing them of extortion:

The business claims that after declining a request to purchase advertising on Yelp, a number of positive reviews from his business’ listing on the reviews site mysteriously disappeared, downgrading the company’s rating on the site. Levitt claims that ten out of eleven five star reviews were removed from his company’s page following his decision not to purchase advertising on Yelp.