That particular topic about Yelp and their reviews have been discussed many times on HN. Yelp is a major scam company that absolutely do not care about the business owner. They are in it for the money -doh- and what matters for them is Page Views, and regular users posting more reviews, thus more page views. Their filtering system is a total mess but since it is a secret on how it works they can say whatever they want... As long as their filtering system goes into promoting page views. Nowhere in there they care about the small business that are badly hurt by their lack of common sense.

Simply don't use Yelp for posting reviews or reading reviews, this is the best thing anyone can do.

PS: I speak from close personal experience with my wife small business being hit hard by Yelp algorithms for filtering review, and Yelp scammy sales people.