-- I was surprised that the HN list page didn't automatically refresh in my browser (seems as though it should be live and not have to be prompted ...)
Imagine:
1. trying to read something long, or
2. going off to a follow a link and to come back and respond,
only to find that the page has been refreshing while you looked away. Now you have to scroll about to find the place you were at in order to respond or to continue reading the comments.
How about a little model of time in a GUI?