Getting Things Done, or GTD as it is popularly known, provides tips, techniques, and tricks for attaining maximum efficiency through a two-step plan - capture all the things that need to get done into a workable, dependable system; and discipline oneself to make front-end decisions for all items in the system - In short, do it (quickly), delegate it (appropriately), or defer it.
What Gina Trapani says
Getting Things Done was one of the seeds that started Lifehacker. It’s a personal productivity book. David Allen was targeting corporate executives, but his ideas struck a chord with the coder community. Software started popping up to help you implement the GTD protocols. After that this idea for life hacks began to float around the web. We launched Lifehacker soon.