Being part of the Ayatana project, a keyboard shortcut hint overlay will be displayed in the upcoming Ubuntu 12.04 LTS (Precise Pangolin) operating system every time a user presses and holds the Super key (also known as the Windows key).
At the moment, in the supported versions of the Ubuntu operating system that support Unity, pressing the Super key does nothing but displaying numbers on top of the app shortcuts present on the Unity Launcher. Pressing the number displayed on the respective shortcut will rise up the window or start the app.
In Ubuntu 12.04 LTS (Precise Pangolin), when you'll press and hold the Super key (Windows key on most keyboards) an overlay hint with all the Unity keyboard shortcuts will be displayed.
This project is still work in progress and no final decision has been made on the default shortcut for this overlay hint. It will work on both Unity 3D and Unity 2D. You can see it in action by clicking the image above.
Canonical hopes that this will fix many issues and bugs reported by users, such as "No guide to the basics of Unity is shown on first login" or "User Documentation should be easier to access".
Ubuntu 12.04 LTS Will Have a Unity Shortcuts Hint