TIL about it after reading this post. It seems to have started around 17/April
From the article:
a login barrier for reading does not really stop AI scrapers because bots can be equipped with accounts within a few minutes. Instead, many suspect that Amazon’s main aim is to increase the number of registered users. After all, those who are logged in can be tracked better – and can be provided with more targeted recommendations and advertising.
Are there open source alternatives to it?



competiion will barely arise because the ai scrape stuff eventually hits a sites profitability. Ai scraping for example is why Rtings went subscription for full review access, as most users dont even bother to click through to the rtings source for recommendations after googling for a product review.
combination of gemini, AMP links and such has basically destroyed text based reviews