“In computer gaming, a MUD (Multi-User Dungeon, Domain or Dimension) is a multi-player computer game that combines elements of role-playing games, hack and slash style computer games and social chat rooms. Typically running on an Internet server or bulletin board system, the game is usually text-driven, where players read descriptions of rooms, objects, events, other characters, and computer-controlled creatures or non-player characters (NPCs) in a virtual world. Players usually interact with each other and the surroundings by typing commands that resemble a natural language, usually English. Arguably modern graphics-based massively multiplayer online role-playing games (MMORPGs), such as World of Warcraft as well as social avatar virtual worlds such as Second Life could be considered MUD variants.
Traditional MUDs implement a fantasy world populated by elves, goblins, dwarves, halflings and other mythical or fantasy-based races, with players being able to take on any number of classes, including warriors, mages, priests, thieves, druids, etc., in order to gain specific skills or powers. The object of this sort of game is to slay monsters, explore a rich fantasy world, to complete quests, go on adventures, create a story by roleplaying, and/or advance the created character. Many MUDs were fashioned around the dice rolling rules of the Dungeons & Dragons series of games.
Such fantasy settings for MUDs are common, while many others are set in a science fiction–based universe or themed on popular books, movies, animations, history, and so on. Not all MUDs are games; some, more typically those referred to as MOOs, are used in distance education or for virtual conferences. MUDs have attracted the interest of academic scholars from many fields, including communications, sociology, law, and synthetic economies.
Most MUDs are run as hobbies and are free to players; some may accept donations or allow players to “purchase” in-game items, while others charge a monthly subscription fee.” See also: MOO, MUCK.