As I understand it, it was something to do with a check being returned. 
I would imagine the attackers figured Microsoft was Microsoft and that
the check would be going back to their main offices.  (It's amazing how
many foreigners I talk to who have no idea what Arizona is, so they
probably didn't know the difference between WA and NV.)

sm wrote:
> > someone nuked MS with anthrax?  YOW!
> Possibly, they're saying now.   Even so, I find it interesting that the
> *licensing* offices were attacked.