[shakna]

Enterprise. A lot of Enterprise applications are required for work, and require very old, very stubborn browsers.

Most emulations don't work.

You need the old stuff (IE), for the old applications to work, and as long as they can force it to, they won't update said old application.

I've even had to touch systems which required IE 4 in the last few years, from before Trident became the rendering engine.