Microsoft late Tuesday made changes to its Windows Genuine Advantage (WGA) Notifications anti-piracy service in Windows XP, a change that should begin appearing on users' desktops over the next few months. The company says it made the changes in order to align the WGA Notifications experience in XP with that of Windows Vista, but the new XP version actually adds an additional twist that's not present in Vista.

"Helping customers identify and buy genuine copies of Windows and avoid pirated software are top priorities for Microsoft," a representative of the software giant told me. "Microsoft is making these changes to simplify the installation process--making it easy for customers to stay up-to-date--to increase the effectiveness of these notifications, and to align experiences across Windows XP and Windows Vista."

WGA Notifications is responsible for alerting users when the copy of Windows they're using does not pass an internal test to determine whether it is genuine or potentially pirated. These alerts have taken different forms over the years. In Windows Vista, WGA Notifications originally moved the system into a reduced functionality mode that allowed only access to Internet Explorer, and then for only one hour at a time. But beginning with Service Pack 1 (SP1), Microsoft changed WGA Notifications in that OS so that the system would be fully functional but include regular, nagging notification messages but the status of the install. This technology also delays logon and changes the desktop background to solid black once an hour.

With this week's changes on XP, Microsoft says it is making the WGA Notifications experience more similar to that in Vista with SP1. That is, the system will still be fully functional when found to be non-genuine, but will feature the delayed logon, hourly notifications, and change the desktop to black on a regular basis.

But there are some differences. First, the new WGA Notifications experience will occur only on versions of XP that are based on XP Professional, including XP Professional, XP Media Center Edition, and XP Tablet PC Edition. These are the XP versions that are "most often stolen," Microsoft says, and over time the company will target just XP Pro, because the other two versions are now much less common. XP Home, which is still being sold with new Netbooks, is not affected by this change apparently.

Second, Microsoft is also painting a non-removable and non-interactive watermark to the bottom right corner of the XP desktop when the system is found to be non-genuine. This watermark displays the WGA logo and the text, "You may be a victim of software counterfeiting. This copy of Windows did not pass genuine Windows validation." In Windows Vista, WGA Notifications does occasionally pop-up dialog boxes with this information, but no desktop watermark appears.

The biggest change with this revision, perhaps, concerns the way WGA Notifications is installed. Microsoft is changing the XP end user license agreement (EULA) to state that WGA Notifications will be automatically-updated via Windows Update going forward. So many users will not necessarily be aware when future updates to the technology are applied. On the other hand, this change also means that legitimate customers will have fewer interactions with the anti-piracy technology, which is probably a good thing.

Also of note is the fact that Microsoft is making such unprecedented changes to XP at all. The company originally released the OS seven long years ago and released is successor, Windows Vista, a full two years ago. This year, Microsoft has made two major changes to the core XP OS, first with Service Pack 3 (which changed the Setup process, among other things) and now with WGA Notifications. Microsoft has never made such sweeping changes to an OS so late in its lifecycle.