Ten years ago, few Facebook users gave a second thought to posts revealing which new restaurant they tried over the weekend. Or taking quizzes that determined which celebrity they might have been in a previous life.

Now that users realize that information is sold to advertisers for a handsome fee and used to pitch new restaurants, movies and even clothes and cars to them, some feel differently, said Makan Delrahim, the assistant attorney general for antitrust enforcement appointed by President Trump.