Multi-User Dimensions/Dungeons (MUDs) are text-based non-graphical virtual worlds.

Multi-user domains, multi-user dimensions or multi-user dungeons are interactive, adventure-type environments where there is a specific goal, and social areas where the purpose is to wander, enter into personal relationships and participate in a community.

MUDs (multiuser domains) and MOOs (object-oriented MUDs) are virtual environments that you enter and participate in. Originally derived from online "Dungeons and Dragons" environments, some MUDs have an educational focus, such as MIT's MicroMUSE. Users can enter the virtual environment and travel between locations - for example, homes, museums, coffee shops, or science labs. Visitors not only interact, but, depending on their level of experience, can participate in the design and construction of the environment itself.

MUDS are text-based virtual worlds in which participants literally construct the world in which they live, writing programs to define the behaviors of objects in the online world. MUDs began as multi-player game environments, but they have evolved into more general-purpose meeting places on the Internet, where people gather to enjoy one another's virtual company and to work together to extend the virtual world. For example, you can decide to be a purple bird and build yourself a nest, or you can become a munchkin and join others in building a replica of Oz.

MUDs provide one approach for collaborative construction on the Internet

Seit ihrer Erfindung sind MUDs evokative Objekte, an denen sich beispielhaft die Probleme der Verantwortlichkeit in der virtuellen Welt aufzeigen lassen.

Die MUDs liefern die Basis für eine handlungsorientierte philosophische Praxis, die als eine Art Bewusstseinstraining für Fragen der Geschlechtszugehörigkeit dienen könnte.

Die Versessenheit, mit der man in MUDs versucht, Leute dadurch 'greifbar' zu bekommen, dass man ihr Geschlecht bestimmt, erinnert daran, wie sehr wir im wirklichen Leben Geschlechterrollen zur Festlegung unserer Beziehungen benutzen.