A California jury ruled Wednesday that Meta and YouTube are responsible for harming users through how their platforms are designed. Legal experts are calling it historic and drawing comparisons to the tobacco industry battles from the 1990s.

Meta and YouTube must pay millions in damages to a 20-year-old woman after a jury decided the social-media giant and video streamer designed their platforms to hook young users without concern for the...

The jurors ruled in favor of Kaley with compensatory damages assessed at $3 million.