Seems at the moment you add stuff to your clipboard when editing your account via the Manage Clipboard option in the Control Panel, which kind of detracts from it's usefulness as I was kind of expecting that there would be like a clipboard button when viewing a post to easily highlight text and add it to your clipboard, hmmm I should explore that and raise a feature request or see if an extension can do it...
However when I tried to use a clipboard entry in a post it gave me the below error:
Error Message: The "ClippingManager" class referenced by "ClippingManager" does not appear to exist.
It isnt a feature I really care about right now though so I probably won't look into that myself for a while.