The FTC report looked at Amazon, Facebook, YouTube, Twitter, Snap, ByteDance, Discord, Reddit and WhatsApp.

Popular social media platforms and video streaming services pose serious risks to user privacy, with children and teenagers most at risk, the Federal Trade Commission found in a report published Thursday.

The report, which stretches more than 100 pages, details the data, advertising and recommendation-system efforts by these companies, and how they rely on information about users to sell ads. Users also “lacked any meaningful control over how personal information was used for AI-fueled systems” on the companies’ platforms, according to the report.

“While lucrative for the companies, these surveillance practices can endanger people’s privacy, threaten their freedoms, and expose them to a host of harms, from identify theft to stalking,” FTC Chair Lina Khan said in a press release.