Here's one straight from the far left corner of left field. Microsoft
has not only filed for, but actually received a patent that essentially amounts to Page Up / Page Down functionality. More specifically, the patent covers a "method and system for navigating paginated content in page-based increments," and it goes on to cite an example of "pressing a Page Down or Page Up keyboard key / button [that] 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." Brilliant, or just plain spiteful?