Built a review site? Fine, but leave the reviews alone. All of them. No, it is not "OK" to close users' accounts with no warning, thereby demolishing all of their reviews. No, it's not OK to "hide" some reviews or to take down reviews when your blackmail tactics actually work. No, Yelp: it's not acceptable to solicit and harass people and businesses who have explicitly posted "no soliciting" signs on their establishments.
Show investors your business model transparently, let's see it. How is this supposed to work legally? Is this really going to be sustainable or build value in the long-term?
If Yelp's public offering gives them anything substantial, we have a lot to worry about. If the IPO market says it's OK for companies to make money by extorting the little guy and stifling the small voices, we are in a world of trouble.