Why does a simple review site drive people so crazy?

The Trilateral Commission. Bilderberg. The Freemasons. RAND Corp. The Illuminati. And, apparently, Yelp. The conspiracy-minded among us have long been convinced that the world is run by a secret cabal of wealthy elite, moving us ordinary folk around like pawns on a chess board for their own hidden purposes. Not content with running the financial system, controlling the government, or installing a new world order, they have apparently set their sights on the tantalizing target of local social media.

At least that's the feeling I got after reading through some of the e-mails and comments generated by my article on Yelp and my follow-up asking for information from anyone who felt that Yelp had wronged them. Many of the e-mails were well-written and to the point. Others called for me and Yelp to burn in hell and to "PRAY PSALMS 140 FOR THEIR DESTRUCTION!" A comment on my story on another Web site called me a pathetic little sack of shit who is carrying water for Jeremy Stoppleman, Yelp's CEO. (Do I have to say it? Not true.) But none, to my mind, offered clear evidence of any sort of plot by Yelp to coerce business owners into paying Yelp to game its own system.

I've categorized the complaints to better explain my conclusion:

Yelp uses high-pressure sales tactics.
Probably true, or at least has been true in the past, and may continue to be so now. But this is also true of many other business-to-business companies. Yelp has built a product that gives it incredible leverage over its target market. As a counterpoint, a small nonprofit I once worked for needed to lease a new copy machine and a few new laser printers. In exchange for the contract, the sales rep offered my boss two new flat-screen televisions, delivered to his home, to sign the deal. My boss politely but firmly asked the salesman to apply the cost of the TVs to reducing the cost of the copy machine. The sales game is quite often one of carrot and stick. And in Yelp's case, it knows it has the stick.

When a business declines to advertise on Yelp, its positive ratings mysteriously disappear.
Lack of evidence. Just to be clear: While I admire Yelp's business model, I would love to catch it manipulating reviews red-handed. It'd be the story of the year. But only an extremely diligent business owner will be able to do this. It would require that business owner to save every Yelp review of his business, record his business's daily star ranking, and wait for a sales call from Yelp. After the owner declines to advertise, he'll have to continue doing the exact same monitoring in order to watch for a drop or any suspicious deletions. And even then, Yelp's regular fluctuations, or a decline in the business's service, could be the culprit.

Kathleen Richards, a journalist who earned Yelp's ire with a mostly anonymously sourced story on Yelp's strong-arm tactics, admirably followed up with a completely on-the-record report. For me, the anonymity Richards granted was never an issue, as I have no reason to question her journalistic ethics. But both stories made clear how challenging it would be to catch Yelp in any duplicity.