Microsoft set out to adopt a formal and rigid support lifecycle in 2002, back at a time when most analysts were expecting to see Windows Vista (then, "Longhorn") within a couple of years. My own point of view was that this lifecycle business had a lot to do with Microsoft's then-new volume licensing scheme, which among other things is oriented towards selling software subscriptions. If you're buying a subscription for software, you can see how lifecycle plans become important. However, delays in Windows Vista coupled with a questionable approach to "consumer" products means that 2007 will carry a few surprises...