Well, VOIP eliminates that one dimensional aspect completely... but yes, you have to be careful of what you say and how you say it online as people can take offense at things you intended as a joke or not take seriously something you don't intend as a joke. The best you can do there is use emoticons but they are a crude tool at best.

Also a lot of people use CAPITAL LETTERS a lot and think that makes them seem more dominant. Generally caps means shouting and as any good Dom should know, once you start shouting you've generally lost control. Ok, you may shout in a session but generally you are using controlled shouting - showing displeasure by raising your voice slightly. A lot of people in an online setting will not take it that way if you 'shout' in chat. Some of them will just block you for being annoying. A dominant 'voice' in my mind is one that is measured, controlled and precise. For example, never using contractions.