Each line in the CB is stored with a timestamp. You can see this by viewing the chatterbox xml ticker (warning: you'll need to be using IE 5+ and/or Netscape6 / Mozilla to see it without viewing source) . When the difference between the current time and the timestamp is greater than a certain value, the line is removed from the list. Note also that the CB is designed to purge older lines after a certain amount of material has ended up in the CB (when everybody's talking, it scrolls by pretty quick).

Philosophy can be made out of anything. Or less -- Jerry A. Fodor