Yelp has an incredibly strong hold on the "review" market. But is their business model one that does what their tag lines promises: "Real people. Real reviews."?
This article gives food for thought -- business owners cannot opt out, Yelp's algorithms -- not consumer reviews determine a business' ratings. If you want to know more about how Yelp, the business works, read, "Yelp, Profits Over People, What Consumers Need To Know."