https://www.siliconvalley.com/2019/04/11/amazon-workers-listen-to-what-you-tell-alexa/

By Matt Day, Giles Turner and Natalia Drozdiak | Bloomberg News

Tens of millions of people use smart speakers and their voice software to play games, find music or trawl for trivia. Millions more are reluctant to invite the devices and their powerful microphones into their homes out of concern that someone might be listening.