I seem to recall certain IIS web servers sending a certain header type that will only trigger a response in IE. When the response is recieved, it then does a bunch of non-legal stuff to spead up the transfer, which of course only works with IE.
If it doesn't get the response, it thens sends out the normal HTML.
So this means non-IE browsers 1st get garbage they ignore, a timeout happens, and then they get the real page.