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 FTC just published results of a sweeping study of social media sites that has been going on for four years. The organization said that many social media sites and streaming services engage in “vast surveillance of consumers in order to monetize their personal information.

The Federal Trade Commission said in a report that major social media companies and video streaming services engaged in vast consumer surveillance while failing to provide adequate privacy controls or safeguards for children.