> I'd always assumed that if you used the TV's UI and if it was connected to the internet, then you'd probably be subject to their ads and data analysis, but it never crossed my mind that they'd perform the same data-analysis over any signal passing through its silicon.
This is discussed in TFA. It's "ACR" (Automatic Content Recognition), and it applies to anything you watch on that TV, via any mechanism you try. Yes, if you hook up your AppleTV and look at your own videos, the TV is watching what you watch.
Today, it's comparing a fingerprint to a database. Tomorrow a new model or a firmware update will have it shipping your pixels to the mothership and doing things like determining who else watched the same video.
And if this isn't enough, you also have to ask yourself: What is your SmartTV doing with the camera facing your hotel room and the built-in microphone?
If a manufacturer uses ACR on content you brought in through the HDMI port, do you trust them with a camera and microphone pointing into your hotel room or home?
If you do trust them not to abuse that, do you trust them to keep all their TVs up-to-date with security patches to prevent hackers from exploiting them and taking over the cameras and microphones?
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I can do this all day. Remember, it's not paranoia if there really is a trillion-dollar surveillance capitalism industry out there buying and selling data, and laundering data so that companies can buy it while having plausible deniability that they were knowingly involved in any illegal or brand-damaging shenanigans.