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Niconico (formerly Nico Nico Douga ニコニコ動画, Niko Niko Dōga, lit. "Smiley Videos") is a popular video sharing website in Japan managed by Niwango, a subsidiary of Dwango. Its nickname is "Niconico" or "Nico-dō", where "nikoniko" is the Japanese ideophone for smiling.
Besides Piapro, niconico is the primary source for VOCALOID Producers to showcase their finished works. As more songs were uploaded to the site, a rank system was created called the 週刊VOCALOIDランキング "Weekly Vocaloid Ranking", which is a ranking of the most popular VOCALOID songs from the past week using statistics from Nico Nico Douga's metrics.
Niconico is most notable for scrolling marquee comments, which has become its trademark in video uploads.
Songs that become quite popular are often remixed, have videos created, or have a number of fans cover the song. In rare cases, some producers may achieve in getting signed with a record company. But more commonly producers release their works using a music service site or creating a CD. Niconico is also a place that brought together, and spawned, many doujin music groups, "Supercell" being a notable example of this.
Niconico continues to be just one of the most popular video sites for Japanese net users, winning awards and entertaining visitors.
As of 30 September 2012, there was 29.46 million registered Niconico users (5.77 million more than at 30 Sept. 2011; 16 million more than at 30 Sept. 2009). 67% of them are male, 33% female. Age distribution: 17.8% - <20, 42.5% - 20-29, 21.5% - 30-39, 12.1% - 40-49, 3.3% - 50 and older. 94% of Japanese aged 20-29 years are registered Niconico users. Niconico has 111.16 million page visits per day, Nico Nico Live - 10.13. 
Niconico is available in Chinese (Taiwanese), Spanish and English. All Niconico accounts work across all sites. An option to link a Facebook account to Niconico is also available. Originally the English version was hosted differently, and linked to Dailymotion, YouTube and Niconico videos. However, comments for external videos are hosted locally, in the past Niconico worked this way, but was changed when YouTube blocked external linking. The English Niconico site seemed to be Niwango's attempt to spread the comment marquee culture into the west, and also may be because of the growing popularity of VOCALOID in the west.
- Niconico on Wikipedia
- Official Site: Nico Nico Douga (Global/Japanese, main)
- Official Site: Nico Nico (English, redirect)
- Wiki: Voca Wiki