MUDs, MOOs, and Collaborative Virtual Environments

   MUDs (multi-user dungeon or dimension) are online games. They use software programs that accept multiple player connections over the network. The software gives each player access to a shared database of "rooms," "exits," and objects. Players navigate the database from "inside" one of the rooms, and they see only the objects located in the particular room that they are in. Players move from room to room through the exits that connect the rooms. MUDs can be viewed as a type of virtual reality, or an electronically represented "place" that can be visited. The interface to the database is generally text based, and all commands are typed into a keyboard. Feedback is most often displayed as text on the computer screen. There are two basic types of MUDs, adventure and social. MUDs originally started as adventure games in which players gained levels based on their success in killing computer-controlled creatures and solving puzzles. These combat-oriented games feature complex interactions between players and the computer-maintained environment. Players simultaneously connected to the MUD can talk with each other in synchronous time. As MUDs progressed, they developed into social gatherings with the ability to create software objects. In social MUDs, people build a new world together, rather than engage in combat.

   MOOs (MUDs-object oriented) add additional objects to the database, such as rooms, exits, "things," and notes. MOOs support an embedded programming language that enables players to describe types of behavior for the objects they create. MOOs facilitate the creation of virtual reality objects that enable the user to experience different types of environments and locations. For example, users enter LambdaMoo through a coat closet and then exit the closet to enter the "living room." LambdaMoo is not a physical environment, rather, it is created through the exchange of written messages. Players interact in a perceptual space.

   With the introduction of the Web, online games have added visual features that enable users to express themselves in new ways. For example, a program called the Palace mixes chat and MUD features together. Users are represented by visual avatars (an embodiment or bodily manifestation), and conversations are displayed in cartoon-like bubbles above the avatar. The term was first applied to CMC by Neil Stephenson in his science fiction novel Snow Crash. As computer graphic technology improves, avatars are being designed to enable users to visually express human characteristics and emotions. Avatars are used in collaborative virtual environments (CVEs) to represent individuals and game players. Collaborative virtual environments are three-dimensional, computer-generated virtual worlds used in games, such as Quake and Doom. Players are physically separated and come together in the visual world represented through the network.