Futaba Channel is a Japanese imageboard website originally born as a mirror backup for the textboard website 2ch (now 5ch). You may be aware of 4chan, which was directly based on Futaba and from which it took much of its culture.

Nico Nico Douga is a video hosting website that was created soon after YouTube's boom. It's famous for having user comments scrolling across videos and for being one of Japan's biggest meme factory from 2007 to 2012. Forcing users to login to watch videos, the push for premium accounts, and a rough transition from FLASH to HTML5 are considered some of main reasons of its decline.

You just reminded me that during the first years YouTube had only a flash video player. It took time until we got a functional html5 video player. Flash was everywhere back then. And before flash players, the only thing we had were the Real Player and QuickTime plugins for explorer and Netscape/Mozilla.

>some of main reasons of its decline.

Also Youtube, and justifiably so for once.

NicoNico was simply obnoxious to use even in its heyday, while you could just open a Youtube vidja and watch. Once Youtube incorporated livestreaming and chat, it was over for NicoNico.