"MUDs are part of the latest phase in a long sequence of mental changes brought about by the invention and widespread use of symbolic tools."
I like this particular quote because it demonstrates the exponential growth which has emerged from technological society. MUD's are a reflection of outer society and provide a means for people to express themselves in an arena. As noted in the text, at first MUD's attracted the fringe computer savy types, but now as they have become more popular individuals are flocking to these online sites and carrying out online lives that are reflective of their thoughts but not necessarily of their true personifications. The article talks about all aspects of the MUD's, the dark sides, creating a page, profile, what people do, and the implications on the individuals outside world.
Drawing back to the original quote, the changes that are occurring in the brain are drawn by addictive forces. No doubt these sites are created to entice it's users to shiny objects that move and stimulate the brain. Couple this with any ounce of insecurity towards conversation with real people, which most are likely to have, and you acquire a fascination with a virtual world. Whether this is beneficial, we have yet to see.