I would like to call the opposite of Skeuomorphism as "Pure Digital" and not "Flat Design", atleast till we get the right word for it. Even in real world there are things that are flat.
Skeuomorphism is also a style of designing digital interfaces but using real world visual metaphors. Eg make a digital button look like a real world button or make a digital clock look like a real world clock. I’m not a hater of Skeuomorphism but that style restricts interaction and visual designers in making full use of the digital world where there are no real world rules.
Eg by basing your design on the interaction and visual elements of a real world analog clock, you are not allowing yourself to think how you can show the time (I didnt say clock. Clock is real world) in a fresh new more intuitive and fun way without losing the goodness of what a real world clock conveys. If you think ‘pure digital’ then you may be able to come with a completely new take at it. Digital is new and we just realized that there is more potential. Like how we started web design using print principles but then now realized it wont scale for all digital devices. There is no concept of scaling in print.
Rus Yusupov, the creative director of the Vine video sharing app, said.
Old things are beautiful, but new things should look, well… new. That’s why Vine doesn’t have a play button. It also doesn’t have a pause button, a timeline scrubber, a blinking red light, or dials and a brushed-metal finish to give you the impression that you’re using a dusty video camera.
Android Designer Roman Nurik did a “fun exercise” to see how skeuomorphism stacks up to some of Dieter Rams’ ten principles. Its Interesting.