What is a MUD?
In the most common definition, a MUD is a text-based online multiplayer game. The acronym originally stood for multi-user dungeon, but over time took on the meanings of multi-user dimension or domain as well. An important aspect that sets MUDs apart from browser-based games, for example, is full interactivity in real time. Most existing MUDs are run as hobbyist ventures and are free to play, but commercial ones exist.
History of MUDs
The history of mudding goes back to 1977 or 1978, when first multiplayer games based off text adventures such as Zork or Dungeon (hence the acronym) started to appear. They first ran on academic networks, and in the 80s, with the spread of home computers and modems, MUDs started gaining wider popularity.
The genre started diversifying as more new codebases were being written and improved upon. Some - also called hack and slash or HnS - concentrated on combat oriented gameplay, others leaned more towards socialising, roleplay or player creativity. The TinyMud family spawned a number of forms, such as MUSH, MUCK, MUSE or MOO, sometimes referred to together as MU*s. Although sometimes incorrectly viewed as separate from MUDs, these are in fact a subset of the genre.
While the vast majority of MUDs are games, the medium is also used for educational or research projects and talkers.
MUDs and MMORPGs
MUDs share many common characteristics with the younger MMORPGs, and the latter are sometimes also referred to as graphical MUDs. Many designers of both kinds of games agree that they are indeed the same thing, but because of the different interfaces, players and those who are not familiar with the inner workings tend to see them as separate.
This perceived difference may further blur in the future, as more and more text-based MUDs adopt graphical or semi-graphical clients.
Playing a MUD
Players connect to a MUD using the telnet protocol, after specifying a host name of the game and the port it runs on. Any machine with telnet and an internet connection is good enough to play on, there really are no other system requirements.
A more comfortable way to play, however, is using a client. Clients are special programs, some of them more advanced than others, with a wide range of features, from a separate input line (almost a must for anybody who plans to mud seriously), ability to copy, paste and highlight text, automappers, aliases and macros etc. A number of clients are free, others are available commercially, but mostly at a reasonable price.