Wow. A lot has happened in Yelp land. The East Bay Express outed Yelp for it's shady business practices. It's been known for sometime that yelp uses extortion tactics to arm twist businesses into sponsoring their pages to the tune of $300-$1000 a month.
Jeremy Stoppelman, CEO and chief henchman of Yelp, has been on an all out damage control media blitz in an effort to spin this story.
His explanations for positive reviews disappearing and negative reviews showing up after it's sales people are turned down by a business include his ingenious "algorithm." You can read about it on his blog (which does not allow for comments btw). In it he blames businesses, anonymous sources, the author.. everyone except himself and the unethical practices of yelp. And for a good laugh here's what he says about anonymous sources..
"Use of anonymous sources is fraught with hazards and is strongly discouraged by most editors"
Correct me if I am wrong, but that is what yelp is all about. Over 70% of the reviews are from anonymous sources. But I guess Jeremy has a problem when the tables are turned and another organization uses anonymous sources. Yelp is all about transparency when it suits Yelp's bottom line but not when it is used to expose the slippery slope that yelp has fallen into.
Judging from comments around the web, it does not look like many people are buying his "explanations."