China 101
Danmu (bullet comments)
弹幕
Real-time viewer comments that scroll directly across the video screen, turning solo viewing into a shared, chat-like experience.
Danmu, literally bullet curtain, is a comment system where viewers' messages fly horizontally across the video at the timestamp they were posted. Imported from the Japanese site niconico and popularized in China by AcFun and especially Bilibili, it transforms watching a video into a crowd experience.
The culture around danmu is distinctive. Viewers coordinate jokes, count down to famous scenes, post warning messages before scary moments, and create shared rituals that a comment section cannot replicate. Creators read danmu reactions as instant feedback, and a dense curtain of comments is itself a sign of a video's heat.
When Chinese media measures a show's popularity, danmu volume is a standard metric. The feature has since spread to iQiyi, Tencent Video, and even some music and reading apps, making it a default layer of Chinese internet culture.