Danmu

Danmu, or danmaku (弹幕), is a video presentation feature in which user-generated comments are overlaid on top of the video as it plays. Each message is tied to a specific timestamp, so it appears at the moment the viewer is watching, creating a real-time, communal reading experience. The concept originated with Japanese platforms such as Nico Nico Douga and was later adopted widely on Chinese sites like Bilibili, Youku, and iQiyi, where danmu became a defining element of the viewing culture.

The comments are typically displayed as scrolling text across the screen, though platforms may also provide fixed positions at the top or bottom and various display options such as speed, color, and font size. Users can usually enable or disable danmu, filter certain content, or customize how quickly comments move. Danmu data is time-stamped, and comments reflect audience reactions, jokes, spoilers, memes, or analysis as the video progresses. In live broadcasts, danmu can be complemented by real-time chat or other interactive features.

Historically, danmu contributed to a distinctive online watching culture, turning passive viewing into an interactive social activity. It has been applied across entertainment, anime, online dramas, and education, where instructors and students exchange comments synchronized with instructional videos. While it fosters immediacy and communal engagement, danmu also presents challenges, including potential distraction, readability conflicts with on-screen content, and moderation concerns.

Overall, danmu remains a prominent feature in video platforms, shaping how audiences perceive and respond to media through synchronized, crowd-sourced commentary.