I like how you sumed it up

> Famo.us is built around a neat idea: by directly using the CSS matrix3d transform in combination with the window.requestAnimationFrame function, you can describe the complete layout and animation of your app in a way that’s hardware accelerated with consistent performance.

> It’s a stroke of genius, but in order to implement that simple idea you need a sophisticated math library to help translate your app’s UI into the series of matrix transformations that get pushed to the GPU. This library is Famo.us.