Microsoft revealed some changes to their Windows Genuine Advantage protection scheme for Windows Vista which determines if the copy of Windows Vista is legit. A non validated Windows Vista operating system would reduce its functionality after 30 days and make only security updates available for that system.
Service Pack 1 will change that behavior. On the good side the functionality will remain and will no longer be reduced, on the bad site this will be compensated by nag screens known from shareware programs that nag the user to buy the application after x days. Windows will use those nag screens and have a 15 second timer before the user will be able to click on Activate Later to continue his work.
Users will still only be able to download system security patches for the system, all other downloads will fail like before. Users who have been using the Bios or Clock Timer hack to activate Windows Vista illegally will face troubles as well. The Service Pack 1 will be able to detect those hacks but there will not be dire consequences either.