Most regular MOO users are strongly involved with those virtual worlds. Education can take benefit from that phenomenon. As states [Ackermann, 1994, p. 13,], ``interactivity is a key to learning'' and ``An increasing number of software designers, cognitive scientists and educators have come to the view that experience is actively constructed and reconstructed through direct interaction with the world, and that, indeed, knowledge is experience''.
The fact that users can create their identities and/or habitats and share them with others augments this ``heads-in'' effect. In a very broad sense MUDs are ``Virtual Realities'' because they form a habitat or micro-world in which many users can play-out some imagined scenario onto a tangible and responsive support (see [Ackermann, 1994, p. 13,] again).