I don't know if this is much different than Windows XP.
The difference is thus:
With Windows XP you can use a retail license at one computer at a time, but as many computers in total as you'd like as long as you uninstall the software from the previously licensed device.
With Vista you can use a retail license at one computer at a time, and only two computers total.
Microsoft defines what a 'new' computer is and what it is not. Tentative lists of the points system that is used to decide this in Vista can be had from MS support and is posted on the web.
Before, activation was only a nuisance, with Vista it will be *boom* no longer legal. Say, you have two computers at home. A main PC and a HTPC that inherits part as you upgrade. You get a new mainboard and processor, swap some parts around and ditch some old ones...
Whoops. Suddenly neither computer is licensed anymore. Too bad.
Everything else is just marketing sugarcoating. If they're really not going to enforce the license change they should rather change the license to reflect policy.
There’s so much contradictory information going around from people who ‘have been in contact with MS’, and the 10 times you’re referring to is an unattributed quote from Bit-Tech. As I stated earlier, believing anonymous PR over the actual license is almost too gullible.
To TechWeb, on the other hand, they say this:
At that point, the customer is able to use the one reassignment for the new device. If, after using its one reassignment right, a customer again exceeds the tolerance for updated components, the customer can purchase an additional license or seek remediation through Microsoft's support services.
No 10 times there. They say that basically you’re at their whim and mercy. Great.
It’s monopolist, draconian, and just plain customer unfriendly, and next time
you can bet your ass they’ll take it one step further still.