Yelp doesn't charge biz owners to respond to reviews, in public or in private. I'm pretty sure about this because I built the feature.

The source of the negative sentiment may boil down to the cold calling. It seems to be one of those things that just hits a nerve, and I wouldn't be surprised if you could trace the anti-Yelp movement to this business practice. The other thing people complain about a lot is that their reviews aren't counted (presumably because of the anti-spam filter). If Yelp fixes those two major problems, it will be in much better shape.

My bad, my bad, what I should have said was something that allows businesses to opt-out of the service.

you want a business with poor consumer reviews to be able to delist itself? Isn't that like being able to delete your case record with the Better Business Bureau?

This is basically the project I started working on a few weeks ago. If anyone is interested in getting together on this, feel free to get in touch (my email address is in my profile). I'm a programmer located in the Mission district of San Francisco.

It would be a nice to have a Craigslist or Wikipedia-style Yelp (fast, lightweight, and non-evil).