If you put up a sign in your yard presenting criminal accusations as fact about your neighbor it is called libel. Do it on Yelp and it is called a review.
If negative reviews on Yelp have gotten you down, unfortunately, there is not a lot you can do about it on Yelp itself. Yelp continues to allow bad, and even unfair reviews on business profiles and refuses to let business owners opt out.
But there are many things you can do to counter their effects -- and paying for Yelp's advertising services is not one of them. From documenting your Yelp profile to branding yourself on Google HotPot (Google's equivalent to Yelp), to deciding whether or not to hire a lawyer, here are tips to help you fight back against bad reviews on Yelp.
Dealing With Lies, False, And Bad Reviews On Yelp
- Part 1 -Will Yelp Remove Unfair or False Reviews About My Business?
- Part 2 -Steps To Take To Fight Back Against Bad Yelp Reviews

Negative reviews on Yelp receive little or no scrutiny while positive reviews are consistently assumed false and subject to rigorous verification. In addition, a new breed of cyberbully has arisen. These are “customers” some newspapers have labeled Yelp Extortionists who threaten establishments with negative reviews unless they receive free services, gift cards, and more.
http://m.eater.com/archives/2012/05/25/yelp-extortionists-threaten-restaurants-with-bad-reviews.php
Thanks for sharing that — you are right. Another issue with Yelp — since so many positive reviews are suspected as being paid for, honestly, I doubt few businesses really do it. But unscrupulous companies now offer go in and post fake negative reviews on your competitors site because negative reviews are not being targeted in the algorithms quite the same way positive ones are. Sort of reverse cheating.