Playing Nobilis Online is, simply put, playing the game via the Internet. Since Nobilis lacks random gaming elements (such as dice), it can be possible to run a game in a forum, mensenger/AIM or through email.
Although most of the social part of the game is lost, or as the author once put "there will be no munchies or snacks for the HG" and there's no way to make players carry on their games if real life calls them during a game.