If it can be gamed for profit, it will be gamed.

> The tactics include pummeling rivals’ listings with overly positive or negative reviews, and repeatedly clicking on links to products they want boosted to trick Amazon’s algorithm into ranking them higher in search results

Amazon is seemingly coming to this realization very late. The downfall of many search engines has been the inability to deal with the tricks that subvert their ranking systems. If you take any external signal as an indication of popularity, it will be manipulated.

The overly positive reviews is an interesting spin on this manipulation; it creates seeds of doubt when a product looks like it's been overly reviewed. The "fake review" is easy to pick out.

[edit: formatting]