[YeGoblynQueenne]

They don't need to listen to your voice for that. The show can have a signal hidden in its sound track that you can't hear, but that the apps on your phone can. Then they can report home that you are watching such-and-such show. No idea what happens after that but I guess google apps share data somehow.

There was an article about this that I read a while back, I'll try to find it if I can.

Edit: here, found something:

https://arstechnica.com/tech-policy/2015/11/beware-of-ads-th...

The ultrasonic pitches are embedded into TV commercials or are played when a user encounters an ad displayed in a computer browser. While the sound can't be heard by the human ear, nearby tablets and smartphones can detect it. When they do, browser cookies can now pair a single user to multiple devices and keep track of what TV commercials the person sees, how long the person watches the ads, and whether the person acts on the ads by doing a Web search or buying a product.

Edit again: to be fair, not even Facebook and Google have the tech to match the shows you watch with ads just by what your phone hears you say. Speech recognition still doesn't work _that_ well.