Lest there be any lingering doubt that everything in the free world can be patented, Microsoft has managed to add 'Page Up / Page Down' to its portfolio. Specifically, US Patent 7,415,666 states:
A method and system in a document viewer for scrolling a substantially exact increment in a document, such as one page, regardless of whether the zoom is such that some, all or one page is currently being viewed. In one implementation, pressing a Page Down or Page Up keyboard key/button allows a user to begin at any starting vertical location within a page, and navigate to that same location on the next or previous page. For example, if a user is viewing a page starting in a viewing area from the middle of that page and ending at the bottom, a Page Down command will cause the next page to be shown in the viewing area starting at the middle of the next page and ending at the bottom of the next page. Similar behavior occurs when there is more than one column of pages being displayed in a row.
We're computer enthusiasts and not legal beagles, but that sure sounds like Microsoft owns the Page Up and Page Down functionality on your keyboard, perhaps paving the way for some interesting royalty demands if the patent goes unchallenged. Think about the number of keyboards, both already sold and those currently being manufactured, and it's easy to see why granting such an obvious patent is troublesome.
Anyone know if the arrow keys have been patented yet?