Dungeons and Dragon online is a computer game by trbine. It is a game with a monthly subsription and takes place in the world of Eberron.
Website located at http://www.ddo.com/
"no" is an utterly ridiculous answer. Whoever put that should have done more research, as all you have to do is google "Dungeons and Dragons Online" and you will find a multitude of links to ddo.com....
If you want to roleplay with humans in a text-based adventure, there are many sites online that do that... a good site that I have used is RPOL (Roleplay Online). See the related link below. There...