Minors in China are now only allowed to use Douyin — the original, mainland Chinese version of video site TikTok — between the hours of 6 a.m. and 10 p.m. for 40 minutes a day, according to new regulations introduced by Douyin’s owning company ByteDance on Saturday, Sept. 18. The rules are enforced via a “youth mode” that underage users must use upon authenticating their identities with the app, which has 600 million users in the People’s Republic. As with its overseas version , Douyin, which literally translates to “shaking sound,” has seen extreme popularity among young users. Apart from...