Yelp just yesterday won a major court case that was trying to prove that they were trying to extort money from businesses by not posting positive reviews unless the business paid for advertising. The plaintiff lost only because the definition of extortion was not met. There seemed to be a conclusion that yes they do suppress the positive reviews for the non-payin businesses. Last I checked my company had 16 glowing reviews. Every single one is buried under the words "16 reviews that are currently not recommended". The link is un-highlighted and is nearly invisible. Yelp is an extortion racket and it is only a matter of time before the courts prove this. Do not click their site and in time they will disappear.
http://www.forbes.com/sites/ericgold...rt-businesses/