Flat design is an increasingly popular trend in web design and is currently the dominant design style in mobile interfaces. Based on simplicity, minimalism, and efficiency, flat UI design eliminates much of the third dimension from the design. According to its advocates, it no longer is necessary to mimic the familiar third dimension in UI design, as people have accepted and adopted the mobile device or are practically born with it in their hands and don't need the third dimension anymore. The mobile device is now ubiquitous and can stand on its own.

No discussion of flat design is complete without a reference to what flat design is not. However, let's start our discussion not by defining it by what is not, but by what it is. Flat design is minimal and basic communication of the interactive and content elements of a design, be it native or web. What it does not exhibit is that ugly word, skeuomorphism—using 3D objects to represent elements in a way that mimics interacting with the 3D world. Flat design sheds drop shadows, 3D objects, textures, gradients, and (mostly in theory) z-indexing.

I'm not so bold as to predict what people will do. History has a way of unfolding plenty of unexpected weirdness that simple and logical folks like me could never expect. However, there are always plenty of fools willing to make bets on trends. The wristwatch was panned a "passing fancy." Some say that Flat UI is only a passing trend and eagerly wait for their familiar world of skeuomorphic mimicry to return. Others say that people's interests are as fickle as a pendulum and predictably swing back and forth. Some cowards take a more hedged approach and say that it will lose its hotness and become just another design option, and some other new trend will be the new excitement. The hipsters were flat before it became cool.