When the Internet was young, or even before the Internet, when computers were young, most of the games you could play on the computer were text-only RPGs. Soon, simple ASCII graphics took over. Then when the Internet was young, it was MUDs all over. Multi-player textbased RPGs. Of course, soon, graphics got better, computer got more powerful, and everyone was aiming for graphics.
Now, a new game is on the horizon, using a recent technology: Wiki's. Here's the description of Lexicon: An RPG. It sounds like lots of fun. If anyone is interested in playing, I can easily set up a game and we can think of a theme to do this with.