"Nico-dō"—is a Japanese video sharing service on the web.

Users can upload, view and share video clips. Unlike other video sharing sites, however, comments are overlaid directly onto the video, synced to a specific playback time. This allows comments to respond directly to events occurring in the video, in sync with the viewer—creating a sense of a shared watching experience. Together with Hiroyuki Nishimura serving as director at Niwango until February 2013,[6] Niconico's atmosphere and cultural context is close to 2channel's or Futaba Channel's, and many popular videos have otaku tastes, such as anime, computer games and pop music. Niconico offers tagging of videos. Tags may be edited by any user, not just the uploader. Each video may have up to eleven tags, of which up to five may be optionally locked by the uploader, but all others may be edited by any user. Frequently these tags are used not only as categorization, but also as critical commentary, satire, or other humor related to the video's content. The site is also known for its MAD videos and its medleys of popular songs on the website, most notably Kumikyoku Nico Nico Douga. Certain original net animations have been distributed on the website, such as Candy Boy, Tentai Senshi Sunred and Penguin Musume Heart.