Every few years, China’s tech industry sees a new bubble: a few years ago, it was Groupon-like services; then it was “O2O” (online-to-offline). Now Chinese investors are speaking of a bubble in live streaming apps, which number in the hundreds.

Open any of these—popular ones include Inke or Huajiao—and you’ll likely see a constellation of young women talking, giggling, and singing to the camera on their phones as if taking an extended selfie. The people doing the broadcasting answer viewers’ questions, occasionally perform songs, and entertain an audience whose size ranges from a handful to a thousand. At any time, users can choose from thousands of chat rooms, each with a different host. Some promote their streams on Weibo, a Twitter-like service popular in China.