. . . Initially, Yahoo mined users’ emails in part to discover products they bought through receipts from e-commerce companies such asAmazon.com Inc., people familiar with the practice said. Yahoo salespeople told potential advertisers that about one-third of Yahoo Mail users were active Amazon customers, one of the people said. In 2015, Amazon stopped including full itemized receipts in the emails it sends customers, partly because the company didn’t want Yahoo and others gathering that data for their own use, someone familiar with the matter said. . . .
Well, this made me go through and check my privacy settings.