If your Java applications make extensive use of Ajax functionality, Comet will be right up your alley as a complementary technique. How about instead of a user initiating an AJAX request to obtain information on your server, it was the other way around, your server 'pushing' information onto a user's browser without any action taken by the user himself ? Well, this is what Comet is all about. Listen to this podcast which discusses the subject, as well as Bayeux, the proposed protocol for standardizing this technique. http://today.java.net/pub/a/today/2008/07/04/j1-2k8-mtW03.html