WebActive. Niconico (ニコニコ, Nikoniko), known before 2012 as Nico Nico Douga (ニコニコ動画, Niko Niko Dōga), is a Japanese video-sharing service based in Tokyo, Japan. "Niconico" or "nikoniko" is the Japanese ideophone for smiling. [1] As of 2021, Niconico is the 34th most-visited website in Japan, according to Alexa Internet.