Smart TVs quietly collect everything shown on screen and sell it to advertisers, which is bad news for anyone who values privacy.

• Once a TV is online and the license agreement is accepted, it can send what you watch back to the manufacturer and its ad partners.
• The TV takes snapshots of the screen many times a second and matches them against a database of shows and movies, even when you are using Netflix, YouTube, or a game console.
• From this, companies build a profile that can include your age, income, location, race, politics, and religion.
• The fine print is designed not to be read: LG's setup involves 10 agreements and 50,000 words, taking three to four hours to get through.

Outlook: Expect this tracking to keep growing unless regulators step in, since almost no one reads the agreements that allow it.