[jodrellblank]

Why would they? Windows 2000 is ten years old, that's longer than the security patch support period of RedHat/CentOS, Ubuntu LTS, Debian, Solaris (and Windows 2000).

Why would or should they go back to developing a free browser for an out of support system which will mess up the user's system as a deliberate side effect, for the benefit of some arbitrary web developers?

[derefr]

It's not really support for their old browsers, though—it's User Experience support for their new ones. Banishing IE6 allows all websites more freedom to use modern formats and specs. Modern formats and specs give them something to compete on in IE9.

To put it another way—if there was an update they could release to Windows 2000, at this point, that people would install voluntarily, but would make more people buy Windows 7 as an effect, don't you think Microsoft would be all over that?