This is so 21st century.
Positive reviews in the iPhone App Store are worth a lot of money to developers.
So they've found various ways to cheat.
The most recent strategy is to use Amazon's Amazing Turk service to globally outsource app review.
Since only people who purchase applications can review them, the author offers to pay for more than the cost of the application.
The catch is the reviewers have to buy the app first, then leave the review with a tell-tale five period marker, then trust the application auther to pay them for the fraudulent review and cover their upfront costs.
It's a measure of the power of Amazing Turk that it found people who were not only themselves crooked, but they would also trust a fellow crook to pay them for their crooked work.
Honor among thieves, apparently.
It's hard to believe this will scale, so I suspect Apple's current comment strategy will work. Even so, it's a classic 21st century crime!