Your smart TV is probably tracking everything that appears on the screen. While ad tracking is par for the course on the internet in 2018, smart TVs are particularly interesting. They don’t just track the shows you stream on their built-in apps: they can recognize any show you’re watching, any game you’re playing, or any ad that appears on the screen — from any device connected to the TV.

This technology — called Automatic Content Recognition and usually provided by a company called Samba TV — is simultaneously fascinating and creepy. It aims to provide more relevant ads and recommendations based on what you watch, which some may find useful — but if you’d prefer not to share everything you watch with TV manufacturers, you can turn this feature off.