We like to daydream, to create our own universes and lives and live them. If we are particularly talented, courageous or confident, we may try to concretize these dreams by writing books, or making movies. We try to share with friends, or indeed the whole world, our own dreams. On the Internet, for nearly fifteen years now, groups of people have gathered to build their own virtual worlds, which they live in and enjoy together. Contrary to the hyped multimedia convergence technologies, the buzzwords of today, these communities demonstrate the power of the written word over other media to express and excite the imagination -- from the original Multi-User Dungeons (MUD) to newer MOOs and other variants, these living electronic fantasy worlds have always been based on text.

Roy Traubshaw and Richard Bartle, two British fans of the role-playing board game Dungeons and Dragons, developed an electronic implementation with extended options and capabilities, and placed it on the Internet. In 1980, a time when the Net was very much a playground for college students, the idea of a fantasy role-playing game with participants from all over the world playing against each other was bound to be popular. MUD1, the original MUD, spawned similar games elsewhere on the Net.

Traditional MUDs provide a description of your surroundings -- 'You are in a dark, damp room. A lamp flickers in the corner. You see a dagger on the floor...' -- and react to simple commands in English-like syntax, such as 'Pick up dagger.' As a role-playing game, you describe yourself vividly to fit into the general storyline, a description provided to whoever happens to meet you. You communicate with other characters, many of who may be human players of the game. However, most MUDs have a number of computer-generated characters, with limited artificial intelligence to control their behaviour and responses, who often play the roles of sages or guides to the MUD, prompting you to do interesting things.

The great popularity of MUDs arises not merely out of the fun of participating, but out of the extent of participation possible. Most MUDs are based on simple programming languages, and 'advanced' players are allowed to modify the code operating it. Users can actually create new objects, rooms, characters and their computer- controlled behaviour, as well as modify and extend the storyline. New MOOs, or object-oriented MUDs, make these tasks even easier and more accessible to users. They allow the creation of classes of things, and let you create a green-eyed, dripping-fanged heebie-jeebie without explicitly redefining everything it has in common with a scaly-faced, red-eyed heebie-jeebie. Life in a MUD is not, therefore, a limited world. You create your dream while living in it.

The obvious use of MUDs is as entertainment, and like video games, MUDs can be extremely addictive. Fans are known to play for 18 hours a day, and alarmed educators in Australia have even banned MUDs altogether. Funnily enough, they need not be harmful to education. The platform they provide for collective creativity can be harnessed to bring out the best in children. For instance, in the experimental Cyberion City at MIT children build and maintain a virtual city themselves, creating shopping malls and housing suburbs.

MUDs are not just for youngsters. At the MediaMOO, where the scene mimics the corridors of the MIT Media Lab, researchers meet in virtual cafes to discuss projects. MUDs are often the sites of Internet-wide conferences for people with similar interests. They provide an electronic environment where participants meet and talk and hold social gatherings.

In the midst of the booming interest in expensive technologies for multimedia, videoconferencing and other future forms of communication and expression, MUDs provide an alternative, thriving on text, low bandwidth and creativity.