I think that there is already a change in the way that we write, and that there are different changes depending on context.
I use e-mail constantly to converse/communicate with my work colleagues. We have developed a chatty style of writing for casual "conversation" messages which has a close analogy to the way we speak when we are face-to-face. We have a totally different style when it is an "Official Communique."
As for misunderstandings - well! The potential for misunderstanding in face-to-face conversation is limitless (especially if you are married to the respondent! ) In some ways, written conversation is better in this respect, as there is time to reconsider a response, and to search for a different meaning. This is nullified, to some extent, in a chat-session such as we have just experienced, of course, but I think that, so long as participants are aware of the potential for misunderstanding and are tolerant, (as everyone is, on this board ) a convention will build up that removes the worst possibilities for dissent (but probably won't remove the potential for descent )