Washington Post: “If you have not used TikTok, you are rapidly becoming the global exception. In five years, the app, once written off as a silly dance-video fad, has become one of the most prominent, discussed, distrusted, technically sophisticated and geopolitically complicated juggernauts on the internet — a phenomenon that has secured an unrivaled grasp on culture and everyday life and intensified the conflict between the world’s biggest superpowers. Its dominance, as estimated by the internet firms Cloudflare, Data.ai and Sensor Tower, is hard to overstate. TikTok’s website was visited last year more often than Google. No app has grown faster past a billion users, and more than 100 million of them are in the United States, roughly a third of the country. The average American viewer watches TikTok for 80 minutes a day — more than the time spent on Facebook and Instagram, combined. Two-thirds of American teens use the app, and 1 in 6 say they watch it “almost constantly,” a Pew Research Center survey in August found; usage of Facebook among the same group has been cut in half since 2015. A report this summer by the parental-control tool Qustodio found that TikTok was both the most-used social media app for children and the one parents were most likely to block. And while half of TikTok’s U.S. audience is younger than 25, the app is winning grown-ups’ attention, too; the industry analyst eMarketer expects its over-65 audience will increase this year by nearly 15 percent. (AARP last year even unveiled a how-to guide.)…”