A California court began hearing arguments this week in what is described as the largest legal challenge Meta has faced, with 29 US states accusing the company of intentionally hooking young users on Facebook and Instagram while violating privacy laws.

A jury in Oakland, California commenced a six-week trial on Tuesday in a case that pits multiple US state authorities against Meta over alleged practices targeting minors. The lawsuit, filed in 2023 by 29 states including California and New York, centers on accusations that the social media giant violated federal and state privacy laws affecting children and teenagers.

During opening arguments, state attorneys claimed Meta knowingly allowed millions of children under 13 to access Instagram while taking minimal action to prevent underage use. They further alleged that internal company research demonstrated Meta understood the negative mental health impacts of its platforms on young people but prioritised business growth over user safety. California's lead attorney presented internal Meta documents suggesting teens exhibited "an addict's narrative about use" and that platform features were "designed to increase time spent" at the expense of well-being.

Meta's legal team contested these characterisations, arguing that the company identified approximately 100,000 such young users rather than millions. The company's representatives also maintained that social media addiction is not scientifically established, pointing to statements from CEO Mark Zuckerberg and Instagram leadership denying that their platforms were designed to be addictive. Meta's attorneys further suggested that privacy laws themselves prevent the company from collecting the data necessary to verify user ages effectively.

The states are seeking billions in damages alongside demands for structural changes to both platforms, including elimination of "like" counts and infinite scroll features. The trial represents a significant legal test of how technology companies may be held accountable for their effects on young users.