"This impartial review was delivered after I received the product free or for a discount"? Give me a break. Joe or Judy Amazon are realistically going to be perfectly happy plunking five stars down for free stuff.

If Amazon wanted to do it right, they'd set themselves up as a neutral intermediary, companies could register to get some amount of product in the review chain, then Amazon would randomly distribute it to relevant reviewers, and the resulting reviews would be posted anonymously (with a known pattern, e.g. 'TrialUser'). And drop any users from the program that consistently give five stars.

Instead, they seem to have created a star-for-stuff system.

Be that what it may for the market: I think they've been a lot less mercenary than they could be (they could likely jack fees a lot higher now without much fallout), but the potential is certainly there.

Great for low cost optimization, bad for great feature development.

PS: The whole only-being-able-to-price-sort-in-a-single-category is terrible too. How do I know if Thing X is in category Y or Z? It successfully reproduces all the fun of wondering what aisle the grocery store stuck trail mix on.