Let's see: in order to make that work, the software would
have to know that you'd viewed the thread after notification,
in order to clear the notification flag so that it would
know that it should send another notification for subsequent
posts. That should be possible, in that it is checking cookies
to know what you've read and not read in order to show the
"unread" flags on your index screen.
I have no idea what standard practice is, as I never use the
function.