> It leads to two perverse side effects. First, producers realize that if brand reputation matters less than a budget for clicks, they will shift to shoddy and cheap versions of their products so they have a bigger budget for clicks.

This assertion lacks evidence. An alternate hypothesis: if you tried to sell literal garbage on Amazon, poor reviews and a high return rate will be visible in the product itself. The ad will earn you a click-through to the product, but buyers will begin to back out instead of following through with a purchase. Ad purchases cannot overcome insufficient revenue - it won't be profitable long-term.

Yes, Amazon has a problem with vendors buying good reviews as well. It doesn't overcome a high number of poor reviews, or a high number of returns.

> And second, Amazon (and Google before it) have an incentive to make their organic search results worse–giving producers more incentive to buy more ads.

Reeks of a conspiracy theory. Most customers simply don't have the time or energy to research any more than the top handful of results. Only a rare person goes 10 pages deep into the search results. Organic search results will produce less traffic when people don't even look at them. But that's not evidence in and of itself that the organic search results were nerfed in some way.

I hate to remind people of the basic truth about modern Amazon, but here goes: the vast majority of the inventory is made in China and the exact same product can be found at a tiny, tiny fraction of the Amazon price on AliExpress and similar sites. The value that Amazon adds is their logistic network that can deliver to domestic US addresses in a day or two, compared to weeks. The difference in price between Amazon and AliExpress justifies sellers spending enormous sums on ads and review purchases, because even if they do sell garbage on Amazon, enough people bought it at such ridiculous margins that the seller can tear down the product with the bad reviews and high return rate and re-offer it under a new brand with the same ad and review purchase strategy and still make a profit. But the person to blame for that is not Amazon, and it's not the seller, it's the fool who decides to pay the ridiculous price compared to the AliExpress price.

Books are one of the categories where they aren't printed in China, they're not sold on AliExpress, and searching for "seth godin the knot" returns the actual correct listing as the first organic search result. So I'm not sure why the author brings his book up as evidence. He might do better by reminding his publisher that "selling on Amazon" is not a homogenous experience and they ought to reconsider flushing money down the drain on advertisements they don't need.

> An alternate hypothesis: if you tried to sell literal garbage on Amazon, poor reviews and a high return rate will be visible in the product itself.

Yeah but at the time when I buy it it's gonna have thousands of 5 star reviews, and the images themselves will be the shiniest most beautiful garbage ever seen by mankind.