What is WSUS I hear you ask? Well, it stands for Windows Server Update Services and essentially, allows administrators to deploy updates across a network, so instead of all the users on your network navigating to Windows Update and downloading the updates separately, just download them once, and distribute using WSUS.
The reason for the post is that WSUS currently does not allow Windows Vista Ultimate Extras to be distributed via WSUS. Not good. A view which is backed up by Erik Neuenschwander, who works in the Ultimate Extras team here at Microsoft "That's not a good situation for customers, so we plan to improve it. The Ultimate team is working with Windows Update to revise the Extras to be offered to WSUS"
Erik goes on to say "We cut support for WSUS at launch to reduce the test burden, and because we didn't think many WSUS environments would deploy Ultimate. We're hearing that we were wrong, so all the Wave Zero Extras will be offered to WSUS later this year."
For more info: Windows Vista Ultimate Blog.
Source:→ TechnetMicrosoft, Windows Vista, WSUS, Vista Ultimate