There are many office jobs out there that don't allow their employees to install software on their computers or give them anything more than what comes with a default XP install, thus leaving them stuck with IE6.

Some big companies simply do not want to take the "pain" of upgrades. I'm working as a consultant now, we are developing a project for a big international company on Microsoft CRM, that specifically works only with IE.

IE6 causes a lot of problems even with Microsoft technology. Nonetheless this client do not want to upgrade their browsers. This is not the first time this happens.