So what is a lifehack? Lifehack.org defines a lifehack by any hack, tip, or trick that gets things done quickly by automating, increasing productivity, and organizing. Lifehacker.com defines a lifehack by any tip, shortcut, or download to help you get things done smarter and more efficiently. From the two definitions, the theme is to get things done quicker.
I like Lifehacker’s definition better, because it mentions getting things done smarter and more efficiently. But my definition of a lifehack is any method that enhances your producitivity to get things done. To me that covers both definitions, in a smaller package.