It is a famous and popular video sharing website in Japan.
Its nickname is "Nico-dō" (or Niconico). "Nikoniko" is the Japanese ideophone for smiling.
You need registration to vew and share video clips and upload videos.
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.
Nico Nico Douga's atmosphere is close to 2channel's (Channel 2) or Futaba Channel's, and
many popular videos have otaku tastes, such as anime, computer game and pop music.
Nico Nico Douga offers tagging of videos. Tags may be edited by any user, not just the uploader.
Each video may have up to ten 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.
You can make registration here;
NicoNico Douga registration
Enjoy video Clips!
*If you need explanation for registration in English, please post comment.
(I will explain it later.)