Windows 9 video leaks: Virtual desktops and Notification Center in action

Another day, more Windows 9 leaks, this time of the new virtual desktops and Notification Center. I've got the videos, and you'll want to see them.
The German site WinFuture posted two videos over the weekend, one showing how virtual desktops work, and one showing how the Notification Center works.
As you can see in the videos below, they're nice additions to Windows 9, although not as nearly useful as the new Start menu. (You can see video of the Start menu here.)
I've used plenty of virtual desktop applications on multiple operating systems, including Windows, the Mac, and Linux. The Windows 9 one looks to be one of the simplest to use, although I'm basing this solely on the video, so it could be more difficult than it seems.

You merely click an icon on the taskbar, and from a notification that appears click an "Add a desktop" button to add a new virtual desktop. You can add as many as you want this way, and then easily switch between them. To close any, click an X as if you were closing a window.
How useful will virtual desktops be? Moderately so, although it's no killer feature.
As for the new Notifications feature, it combines an existing tool, desktop notifications, with a new feature that alerts you to a variety of actions, such as messages via Skype. The notifications appear momentarily onscreen, then fade away. You can pull up them all up on a screen, click any to see more detail, close any individually, or clear them all at once.