It's a server address. You'll have to use telnet or a program like "SimpleMU" to connect. The most user-friendly way to get on the game is to download SimpleMU here http://simplemu.onlineroleplay.com/download.html
then when you run the program, you go to file>new connection wizard and follow the steps there. dragonet.afraid.org is the "site address" and the port number is 9193.