In my Ajax session today at the Boise Code Camp I mentioned a new technique I'd heard about. It let's you send data to the browser, without a request from the browser. Someone has called this Comet, and here's an Ajaxian article about it. This is common in other applications, of course, things like instant messengers. But if this becomes widespread on the Web, we will see some pretty cool browser based apps. We'll have to keep security in mind though. I'm sure the shady folks will come up with lots of bad things to do, once they can send stuff to your browser without a request.