https://en.m.wikipedia.org/wiki/MUD https://en.m.wikipedia.org/wiki/MUD Basically a text-based adventure like Zork, except on a server, with persistent state,

https://en.m.wikipedia.org/wiki/MUD https://en.m.wikipedia.org/wiki/MUD Basically a text-based adventure like Zork, except on a server, with persistent state, and all the players visit the same "world"