The Christian Science Monitor has a good piece this week on why we can't really communicate emotion well in e-mail. There's a bunch of interesting stuff in the piece, but my favorite bit was a study by Professors Justin Kruger of New York University and Nicholas Epley of the University of Chicago who looked at how well sarcasm is picked up on by people reading their e-mail.
"Their conclusion: Not only do e-mail senders overestimate their ability to communicate feelings, but e-mail recipients also overestimate their ability to correctly decode those feelings.
One reason for this, the business-school professors say, is that people are egocentric. They assume others experience stimuli the same way they do. Also, e-mail lacks body language, tone of voice, and other cues — making it difficult to interpret emotion."
Basically, I think it means that most people are bad writers. When writing, they hear what they're saying in their head, with all of the emotional cues sitting there, but they don't realize that they aren't communicating those cues in text. It's not that emotion can't be communicated through writing, but that it isn't as easy as everyone thinks it is. Because of the diminished emotional bandwidth of the written word, you have to be very careful about phrasing, description of emotional state and the tonality of print versus voice.
It's like that old trope... everyone may have a book in them, but do you really want to read it?