Watching your contact type ... nothing new ?

From the dark past, where instant messaging was still associated with a flower that shifted between the colours red and green, and messages had an annoying "oh oh" sound, I remember the feature where you could see your contact type every character.

A blogpost from 2008 confirms this as well, although I can't seem to find any screenshots.

Of course, you were typing in your own little window there, and didn't have any concurrent editing options. But they did have the character per character communication.
It would be interesting to see the technologies compared. It's already sure that connection response times won't pose any theoretical issues, if even non-broadband connections could handle this.