Discworld was the first MUD that I ever played and I was amazed by the number of things that you can do. With 5 completly different guilds, player owned shops and houses, and an advanced combat system. But the thing that amazed me the most was the flavor of the whole world which managed to keep the feel of the entire book series while giving players a flexible playing experience. I have tried other tecknically more advanced MUDs such as Ateolia and stopped soon afterwards because they simply failed to have the unique charm that discworld has. All in all it is a very advanced MUD that makes up for some very minor limitations by being a great place to hang out, chat, PK, and just plain have fun.