See "Yelp and the Business of Extortion 2.0" => ( 2009 ) http://www.eastbayexpress.com/oakland/yelp-and-the-business-...
EDIT 2: Mobile view (1st page only) if browsing from iPhones, Droids... https://web.archive.org/web/20160709054149/http://m.eastbaye...
I remember being alarmed that time when I read this. So I asked a local Indian Restaurant owner located on 2nd Street and Market Street here in San Francisco, with who I had become good friends with, since he was from the same city as my dad (Bombay).
The restaurant used to be called "Bhindi". The owner pretty much confirmed everything in that report. He even told me that the Yelp Marketing guy threatened to display his low star ratings on top and completely hide true 5-star ratings if they (the restaurant) did not buy at-least 300$ worth of ads from Yelp every month. Eventually that restaurant went out of business (don't think it was related to the Yelp Extortion 2.0 though, definitely didn't help either) and now there's Mehfil in it's place.
EDIT: Her follow up story: "Yelp Extortion Allegations Stack Up" https://web.archive.org/web/20090616170118/http://www.eastba...