Sounds like a cool new form of space travel, doesn’t it? Unfortunately, (or fortunately, depending on how you look at it) it’s just a trick to make navigating pages in your web browser a little easier.
So, instead of using the Page Up and Page Down keys all the way on the other side of your keyboard, do this:
Press your Space Bar to go a page down.
Press Shift+Space to go a page up.
Quick navigation, without traveling all over the place! Give it a try!