ну вот пачка интересных ссылок например:
https://blog.pipecandy.com/amazon-market-share/ (там ссылки на источники есть)
Amazon is a search engine, and the largest search engine for eCommerce. 54 % of product searches now take place on Amazon. If we were to exclude YouTube as part of Google, Amazon is technically the second largest search engine in the world!
Subscription service Prime now has around 103 million members in the US. That’s more than 50% of all US households!
Amazon would not like you (or the antitrust hawks) to realize that the US’ single largest eCommerce entity is its third-party Marketplace. It accounts for about 31% of all US eCommerce (ещё 17% - продажи самим амазоном)
Take a look at the top 10 marketplaces’ sales and you’ll see that Amazon is not just the biggest of them all, but it is bigger than the other 9 marketplaces (eBay, Etsy, Best Buy, Walmart, etc.) combined.