https://www.theguardian.com/technology/2017/oct/30/facebook-denies-eavesdropping-on-conversations-to-target-ads-again >Social network’s head of ads dismisses rumours that Facebook app uses smartphone mics to listen in, serving ads against what it hears >Facebook has again denied eavesdropping on conversations to target adverts, following persistent speculation on the part of users who have received suspiciously timed promotional messages.