That's a question I'll defer to entropy who wrote the script. It looks like the script runs on a timer to show the info every 600 seconds (10 minutes), however I think it just shows the current top stories even if it's a repeat, and it doesn't seem to have something to detect when there's something new (or not).
Also, because I'm paranoid, it's probably a good idea to modify the script slightly.
now:
msg %y %main
new:
msg %y $remove( %main , $cr , $lf)
