There have been a lot of posts on the interwebs this Summer on supporting Internet Explorer 6 (IE6). Recently on the Digg blog there was a post from one of the engineers that they have very low usage from IE6 at this point, so they are dropping support.
Ina Fried also had a post on how Microsoft is having a hard time getting companies to upgrade to newer version of IE. I am currently building web applications for business users, and as much as I would like to stop supporting IE6 it still has a 40 percent market share in the financial sector.
Hopefully with Windows 7 coming out soon, more companies will start to upgrade their PCs with this new operating system.