If you bought a new smart TV during any of the holiday sales, there’s likely to be an uninvited guest watching along with you. The most popular smart TVs sold today use automatic content recognition (ACR), a kind of ad surveillance technology that collects data on everything you view and sends it to a proprietary database to identify what you’re watching and serve you highly targeted ads. The software is largely hidden from view, and it’s complicated to opt out. Many consumers aren’t aware of ACR, let alone that it’s active on their shiny new TVs. If that’s you, and you’d like to turn it off, we’re going to show you how.