Imagine GE selling a light bulb and saying
you can use it in ANY compatible lamp, but if you decide to put it in
another lamp after the first one you put it in, it won't work.
-Rob
That's a whole other story... you cannot make a copy of that light bulb and
give it to someone else. Nor can you use that same light bulb in 2 different
sockets at the same time. You are free to move that lightbulb around and
use it where you wish, as you can with XP. The only difference is you have
to make a phone call to do it.
They don't prevent you from installing the same copy of the software on a
different machine, so long as it's the only machine you use it on. I switch
hardware, rebuild PCs very frequently and have had to call to activate many
times, and I never had any trouble activating. True, it's a but of a hassle
to have to call and read those numbers several times, and to try and
decipher what the person in India is telling you to type, but it's never
prevented me from using the copies of XP I paid for.
I wish activation would go away, too! To compare software to alight bulb is
apples to oranges.