Most of the "Yelp is extortion" line comes from businesses that have had good reviews hidden (that they probably gave people discounts for, or paid for.) Every good hidden review is seen as an outrage.
It'd be less controversial to kill bad reviews like this (because bad reviews often can be extortion or attacks on competitors), but the users would notice and also bitch. [edit: even worse, businesses that got bad reviews deleted by talking to Yelp might be characterized as "in bed with" Yelp.] A Yelp-like business is no-win imo. Voting isn't much of a signal if you let anybody who happens to walk by vote.
It'd be less controversial to kill bad reviews like this (because bad reviews often can be extortion or attacks on competitors), but the users would notice and also bitch. [edit: even worse, businesses that got bad reviews deleted by talking to Yelp might be characterized as "in bed with" Yelp.] A Yelp-like business is no-win imo. Voting isn't much of a signal if you let anybody who happens to walk by vote.