A jury in LA has delivered a damning verdict for two of the world's most popular digital platforms, Instagram and YouTube, BBC reports.
It ruled those apps are addictive, and deliberately engineered that way – and that its owners have been negligent in their safeguarding of the children who have used them.
It's a sombre moment for Silicon Valley and the implications are global.
The tech giants in this case, Meta and Google, must now pay $6m (£4.5m) in damages to a young woman known as Kaley, the victim at the centre of this case.
She claimed the platforms left her with body dysmorphia, depression and suicidal thoughts.
Both companies intend to appeal, with Meta maintaining a single app cannot be solely responsible for a teen mental health crisis.
Google, meanwhile, says YouTube is not a social network.
But for now the ruling means "the era of impunity is over" according to Dr Mary Franks, a law professor at George Washington University.
