The Australians have decided that IE6 is no better than rotten Milk. The Register article
We have seen issues with IE6 and older versions of flash causing problems in some situations. The fact is IE6 opens you to security vulnerabilities that the bad guys are waiting to exploit. Upgrade your browser today or try out any of the many options available.
Often it is a corporate decision, IT not willing to upgrade across and environment. Sometimes people just don't want to learn a new interface. That makes you susceptible to exploits and puts your data at risk.