Overall the technology we designed for Windows Vista allows Windows to better protect itself and be updated over time. As a result, Windows Vista is harder to pirate, and we’re seeing fewer copies of non-genuine Windows Vista on customers’ machines. Windows 7 includes the latest generation of this technology and provides the technical foundation of our ongoing anti-piracy efforts.
Vista's SP1 introduced some new technology for this activation compared to the Windows Genuine Advantage that is used on XP. Windows 7 supposedly takes this even further and makes the whole activation process a lot smoother and understandable.