On a Tuesday morning in Oakland, California, a lawyer stood before a jury and read from Meta's own files. The words were not from a critic or a regulator — they came from inside the company itself: "Teens have an addict's narrative about use." With that single internal research note, the biggest legal challenge in Meta's history was formally under way. The case was brought in 2023 by 29 US states, led by California and New York, and it accuses Meta of systematically hooking children on Facebook and Instagram while concealing what its own researchers had found.

Megan O'Neill, a lead attorney for California, told the jury that Meta's business model could be reduced to four verbs: hook users, hold them, harvest their data, and hide the truth. She argued that internal documents — including emails and chat logs that reached all the way up to Mark Zuckerberg — showed that features designed to maximise time spent on the platforms were known to conflict directly with users' well-being, yet were kept in place because profits consistently outweighed safety. The two sides disagreed sharply even on the most basic numbers. California claimed Meta had identified millions of 11- and 12-year-olds on Instagram and done little to remove them; Meta's lawyers countered that the figure was just over 100,000, and further argued that social media addiction, as a clinical concept, does not exist.

The states are seeking billions of dollars in damages and are demanding structural changes, including the removal of like counts and infinite scroll — design choices they say are engineered to maximise engagement at the expense of adolescent mental health. The trial is expected to last six weeks, and its outcome could reshape how platforms across the world are permitted to design products for young people.