Even when they stop doing this, businesses will still get mad. They are mad that one bad employee can mistreat one customer, and the Whole Internet will hear about it (because Yelp is actually popular). The extortion claim is the only way to get Yelp into court.

In the end, the local businesses will lose. And I think that's a good thing; they should hire good employees and provide good customer service! I'm glad that Yelp can make some money off their indifference.