Windows only: WizMouse is a handy little application that enables scrolling of non-focused application windows with your mouse wheel. It's as straightforward as it sounds. When WizMouse is running in the background, you can scroll any window by putting the mouse cursor over the application and spinning your mousewheel (instead of having to click on it and redirect the focus to that application). One bonus over similar utilities, like KatMouse, is that for the odd or vintage program that doesn't support mouse based scrolling, WizMouse converts the commands from the mouse wheel into scroll commands. Although at first glance it may seem trivial to have to click on a window before scrolling in it, after a short period of testing the application I'm amazed the feature isn't built right into Windows—it's a godsend for dual monitors, or anyone monitoring a vertically-focused website. WizMouse is freeware, Windows only.