The Wall Street Journal created dozens of automated accounts that watched hundreds of thousands of videos to reveal how the the TikTok algorithm knows you so well.
A Wall Street Journal investigation found that TikTok only needs one important piece of information to figure out what you want: the amount of time you linger over a piece of content. Every second you hesitate or rewatch, the app is tracking you.
Photo illustration: Laura Kammermann/The Wall Street Journal
