Automatic content recognition is one of the freakiest kinds of tracking I've heard of. Smart TVs become data collection hubs for the home if they get connected to the internet. Some have microphones for voice recognition. If you go into the privacy policies for them, you'll find that your audio gets sent off to third parties (albeit only when in use).

I completely disconnected my TV from the internet, but it still prompts me to connect it to Wi-Fi, to agree to policies, etc. This page is full of horribles: https://www.consumerreports.org/electronics/privacy/how-to-t...