People connected from around the word to interact in these text-based environments. Many MOOs existed purely for entertainment, but others had higher aims, such as facilitating intellectual discourse (Postmodern Culture MOO) or revolutionizing the way we thought of classrooms (Diversity University). What's most intriguing about these environments nowadays is that a) no one has ever heard of them, and b) the way we approach education is mostly not revolutionized by their once-upon-a-time prevalence. This makes me think twice when I hear something claim it's going to change everything.
PMC MOO screenshot
I use, like, and benefit from modern technology, the internet, and "web 2.0" technologies, but I like to maintain proper perspective, too.