http://www.itwire.com/content/view/20193/53/
Microsoft granted Page Up Page Down patent
http://www.patentstorm.us/patents/7415666.html
US Patent 7,415,666 goes under the snappy title of: "Method and system for navigating paginated content in page-based increments" and is the latest to be granted to that serial patent application junkie better known as Microsoft.