There is no two way of saying it - IE is just not friendly to AJAX developers.
So when I go to the New York Times, the very first thing I see in IE is this:
So I have to click on the dialog box to dismiss it. Then it comes again, so I have to click again. Then and only then the front page shows.
This is the reason why most developers I know use FireFox to develop their apps, and then port it to IE (for a bunch of them, that IE is running on a virtual machine on a Mac, see my post about Vista).
Microsoft is probably one of the best companies to fully appreciate what allegiance of the developers (or lack thereof) is worth. And it is losing it fast in the AJAX space, because of the terrible tools.