If you haven't watched the video regarding HUD on the blog posted by Mark Shuttleworth which is linked in that press release then I highly recommend doing so. In less than 3 minutes you will understand the intended direction.
Blog post: [markshuttleworth.com
Direct link to YouTube video: [youtu.be
I also like the idea, personally. But a feature I would love to see is the real-time display of style changes that are offered by the Microsoft ribbon when hovering over a selected element while using an application. In the video example we see the author apply an update to a cube in Inkscape but then having to undo the change because it was not the expected result. Whereas the MS ribbon works like a preview mode without actually clicking and applying the change. You select the item on the page to which you want to manipulate and then by hovering over options in the ribbon menu you can see how the end result would appear by merely moving your mouse over the menu options available in that particular context.
Who knows, perhaps this is already planned for the HUD feature and I'm just not aware of it! If anybody knows differently can you point me toward the resource describing as such?