We had a similar issue over at Extreme Kung Fu where I teach out of. A Yelp rep called (this was maybe a year or year and a half ago) and same thing: We notice you have a lot of positive reviews and we drive a lot of traffic to your site. The implication of the conversation was that if we wanted to stay that way, we better sign up as a sponsor.<p>I even wrote a blog post about it, and that got picked up when the whole Yelp thing blew up last year. I used to recommend Yelp to everyone, now I feel dirty even talking about it.