How do you take a screenshot with the UI up versus clearing the UI?
Only way for that is to use a third-party program that allows taking screenshots (such as Fraps). SE only allows you to take screenshots by hiding the interface (was this way in FFXI, too).
Interesting note: unlike in FFXI, hiding the interface will now show the copyright notice even in external screenshots/video capture. (Maybe it shows on-screen, too, not sure since I play on a TV and the bottom is cut off a bit.)