This helps a lot because we don't have true page up and page down keys. The advertised key command involves the 'fn' key which is all the way on the left and the arrows which are all the way on the right. Grrrr.
Also, just in case people don't know, command plus the up/down arrow keys navigate to the top/bottom of the current page, and command plus the left/right arrow keys mimic the "back" and "forward" buttons.
[Editor's note: These keyboard shortcuts work on desktop machines as well, since they are features of IE itself.]

