Comment by afiori

On the other hand it might point to something more serious, that the level of tracking Facebook and Google use lets them loosely predict what you are going to think about.

So maybe the microphones are safe and pristine, but we should be worried and appalled the same as if they were actually listening.

I like to think about it sorta thermodynamically: consider your behaviour under the blurred lens of interests, what you buy, what you read, how you react to news, etc, in this model humana have, let's say, n bits of entropy; how many of those bits can Facebook decode?