And iChat's use of the speech bubbles for IM dates back to 1997:
http://jens.mooseyard.com/2008/03/the-origin-of-the-ichat-ui...
A very novel UI at the time.. here is a cached version of the broken pic: http://6.media.tumblr.com/MitMvSO0c6w81bbgrsKunjNE_500.png