Agreed that their recommendation engine is nearly useless. But that's not really where the data benefits them. The power is in aggregate data: Product sales hi

Agreed that their recommendation engine is nearly useless. But that's not really where the data benefits them. The power is in aggregate data: Product sales history, trends, etc.. The things you can do with that kind data, in that volume, across nearly endless markets and verticals... Throw in an army of third party sellers paying you while they do your research and power your analytics for you for free: The real mystery is that they're not eating the internet retail industry faster.