I think Phillip Greenspun has probably earned enough reputation in the hacker community that we can assume he isn't trolling, especially considering the update

I think Phillip Greenspun has probably earned enough reputation in the hacker community that we can assume he isn't trolling, especially considering the update he posted. The fact that a bunch of legitimate positive reviews vanished shortly after they were posted certainly looks suspicious from the point of view of a business. Yelp's sales calls are known to include offers to restore hidden positive reviews and hide negative ones in exchange for a fee. That sounds an awful lot like extortion to me. Furthermore, as a user, I know I can't trust the information that appears on Yelp.