For years, Facebook, now renamed Meta, has offered a code called pixel to businesses. By embedding pixel on their websites, those businesses can collect information on users, then target them with ads on Meta’s social media platforms. The investigative news website The Markup has been looking into how some of the personal information pixel gathers is shared back with the tech giant. Meta says its policies make clear that advertisers should not send sensitive information about customers through its business tools.

But Colin Lecher, co-author of a new Markup investigation, is reporting that students are among those the pixel code tracks.