Deciding to eradicate Sony's root kit is probably one of the most decent things I remember Microsoft doing in a long time. I do not know what kind of effect it will have on their relationship with Sony, but it is a very clear and proactive stand on the issue which will set the tone for setting the limits on what can be termed as acceptable behaviour in dealing with piracy.
For those who are late in joining the party, the story goes something like this. The story broke after Mark Russinovich of Sysinternals posted on his blog that Sony was installing a root kit as a part of their copy protection mechanism. Sony responded by issuing a patch that Mark said was capable of crashing the systems which installed it. Finally, Microsoft steps in and decides to zap the root kit. Detailed FAQ by CNet here.
Update: I am taking Google Analytics for a spin here, so other than the Sitemeter tracker I now have one more way to keep an eye on you all.