If you haven’t already noticed, flat design is so in right now.
So what is flat design? It’s design. That’s flat. It revolts against skeuomorphism. In UI design, skeuomorphism usually refers to a digital element designed to emulate something from the real world – think of the leather stitching that boarders the calendar on an Apple device or the faux pine bookcase in iBooks.
Skeuomorphism was introduced to help us make sense of new technology, i.e. If if looks like a real button and shines like a real button it must mean I’m meant to push it.