Do you project personality when you type? I would like to think I do, but there again maybe I don't. I can hear the words in my head as I hit the keys - my tone and my sentence structure. Does your interpretation of one's writing differ depending on your relationship with that person? I would like to say that it doesn't, but truth is, it probably does. If you're mad at someone, something harmless may be taken as cynical. If you care about someone, a simple hello may be blown out of proportion. We often miss visual reactions and casual tone of voice when conversing via the internet.
Emoticons are one way of showing emotion. A smiley face :) to show happiness, appeasement, lightheartedness. A sad face :( to show sorrow, dislike, or discontent. There are many other icons like this one :-/ showing confusion or thought. They all represent somewhat human expressions. I try to use them especially during IM conversations. I like to think people know if I'm serious or joking, being playful or not. But I guess the truth is, you don't know how others interpret you. Sometimes you can gauge their misinterpretations by their reactions. Other times you move along as if nothing happened.
Just a random thought.