I find the idea of “distraction-free” writing apps to be bunk: after all, why on Earth would the presence or lack of a menubar make any difference to your ability to concentrate? I am, however, a sworn enemy of clutter, and so I immediately downloaded the $0.99 Focus app, which is kind of like a virtual rug under which you can sweep your mess of Mac application windows.
Focus Fades Non-Active Apps Into The Background