A little over a year ago, social media companies were put on notice for how they protect, or fail to protect, their youngest users. In a series of congressional hearings, executives from Facebook, TikTok, Snapchat and Instagram faced tough questions from lawmakers over how their platforms can lead younger users to harmful content, damage mental health and body image (particularly among teenage girls), and lacked sufficient parental controls and safeguards to protect teens. Those hearings, which followed disclosures in what became known as the “Facebook Papers” from whistleblower Frances Haugen about Instagram’s impact on teens, prompted the companies to vow...