FurryMUCK

The first MUDs appeared in 1978 and provided a text-based virtual world focused on adventure. While the first MUDs were clearly focused on the game, things changed in 1989 when Jim Aspnes released TinyMUD. TinyMUD allowed users to focus on building and socialisation, rather than RPG-style game playing. It soon emerged as the "most popular MUD on the internet", and a subculture of furry fans emerged within the system. These players "described themselves as anthropomorphic animals" and proved to be "somewhat controversial".

With TinyMUD's success a number of alternative systems derived from TinyMUD's basic architecture emerged. One of these variants was TinyMUCK, a program originally developed and released by Stephen White. Piaw Na became interested in White's TinyMUCK in 1990 and decided to implement Forth as the programming language for development within the environment. 0, which became the core to Na's short-lived AtlantisMUCK, which was launched in 1990.