Skeuomorphism in design: What is it?

You may have heard the term skeuomorhpism bandied about recently, especially with regard to several Apple iOS and Mac applications, like Calendar or Address Book. Essentially, it means taking design cues—and sometimes whole pieces—of real-world objects in computer interface design. For example, Apple's most recent versions of its Calendar app use a faux leather stitched top bar to simulate a real desktop calendar.
This type of design is one of those love it or hate it kinds of things. Most folks are not neutral about it. (In fact, Apple recently fired the executive who was generally held responsible for this kind of direction at the company.) But it can be explained neutrally, and this presentation does a pretty nice job of doing just that and comparing it to visual metaphor, which is an entirely different design technique.

Skeuomorphs & Visual Metaphors in UI Design