Smart TVs from LG and Samsung are increasingly being used as monitors for Mac and PC, given that they are generally cheaper than an OLED display. The trade-off that you get for an inexpensive TV is adware. To accomplish this goal, they can capture screenshots of everything on screen, and sell it to just about anybody who asks, or they use that data themselves for targeted home screen advertising.
Smart TVs are not just screens you watch. They are also sensors that watch you. LG and Samsung smart TVs both include technology called Automatic Content Recognition, or ACR.
The feature captures small snapshots of what's on your screen or snippets of audio, then sends that data to external servers to identify exactly what you are watching.
ACR works even when the TV is used as a PC monitor or connected via HDMI. A 2024 study [arxiv.org] by University College London and collaborators found LG TVs capturing screenshots as frequently as every 10 milliseconds.
Samsung TVs do so every 500 milliseconds — even when displaying content from external devices. Opting out of ACR in settings completely stops this network traffic.
Each snapshot is matched to a massive database to determine the exact program or ad. They allow companies to build a detailed profile of your viewing habits.
https://appleinsider.com/inside/mac/tips/how-to-stop-your-lg-or-samsung-smart-tv-from-tracking-you [appleinsider.com]