CBS NEWS - YouTube and TikTok's popularity among teens has skyrocketed in recent years, while other social media platforms, like Facebook, have seen a decrease in teens using their services. 95% of kids ages 13 to 17 say they use YouTube. And 19% say they use YouTube almost constantly. TikTok is the second most popular among this age group, with 67% of 13 to 17 saying they use it. On top of that, 16% say they use TikTok almost constantly.