Nico Nico Douga is a popular video-sharing website in Japan managed by Niwango Ltd. Its nickname is "Niconico" or "Nico-dō", where "nico nico" is the Japanese onomatopoeic expression for smiling.

Its the main difference from other video sharing services is that it enables users to write comments as text that appears on the actual video screen and flows from right to left across the screen, against any timeline or scene of uploaded videos by users. With this special feature, NND has retrieved a missing sense of unity in the vast internet world, which removes synchronism. Commenting video-timeline users can be veiled by a sense of unity as if they shared the scene with other users in the real world. (e.g., the social atmosphere and communication like any conversation between family members and friends while watching TV in a living room.) In addition, videos with comments transform themselves into another communication/art/work form because they differ from original videos in terms of additional objects. Under the process of adding comments to the videos, the videos are to be transformed into more valuable objects as well as inspiring other users to create the new value exponentially. Adding elements of comments to videos provides a common experience as if users were sharing the atmosphere and watching the videos together in real world. Creating more valuable video work, aiming at those who have a common experience, all users dynamize together again. Those who create original videos participate in the collaborating video party, which often generates ultimate chefs-d’oeuvre, generating a massive collaboration spiral since the launch of NND.

Nico Nico Douga (JP). There are two core teams supporting NND: Dwango staff, and Mr. Hiroyuki Nishimura, a founder of 2channel, the largest BBS in the world. While over 100 Dwango staff currently engage in planning and operating NND, the main participants in the project are users of NND. The participants’ breakdown is as follows: video posters: 200,000 users; commentators, accelerating video value: 1,000,000 users. As NND is a free service with ID registration, anyone interested is able to participate in the service.