> There is a difference between an icon and a real skeuomorph design. How would you represent a pen without drawing the shape of a pen otherwise ?

I wouldn't; personally I don't think there is anything wrong with using real world metaphors to make a point.

The trend seems to be moving away from realism in design, not skeuemorphism.

I think that having rendered textures that emulate leather became a trend in the first place because of high resolution screens; having some intricately designed texture was a great way of showing off how amazing the screen is.

Now that high resolution screens are the norm, there is no need to show it off, which is why the flat ui trend is emerging.

> The trend seems to be moving away from realism in design, not skeuemorphism.

Yeah, exactly. Even if you don't simulate the look of paper (e.g.: texture), if the design functions like paper, it's skeuomorph just as well.

> Now that high resolution screens are the norm, there is no need to show it off, which is why the flat ui trend is emerging.

I think the reason is we have a native-digital generation that doesn't benefit from the connection to real life objects anymore. Those designers are all on their 18's.

For instance, the recording app on iPhone features a VU meter. How many people buying phones today have seen a real VU meter?

No, faux leather isnt skeuomorphic.

The bookshelves in iOS's iBooks app are. But these could easily be drawn in a Flat UI 'style' and still skeuomoprhic style.

So rich textures != skeuomorphic

Faux leather and textures in and of themselves aren't, but using a faux leather texture on a notebook app to make it look like a real notebook certainly is.

skeuomorph is a physical ornament or design on an object made to resemble another material or technique. Examples include pottery embellished with imitation rivets reminiscent of similar pots made of metal,[1] or a software calendar application which displays the days organised on animated month pages in imitation of a paper desk calendar.[2]

Simulated woodgrain on automobiles is a skeuomorph, such as this station wagon which uses no actual wood construction

http://en.wikipedia.org/wiki/Skeuomorph

Same Wikipedia article: "Functional input controls like knobs, buttons, switches and sliders are often careful duplicates of the ones on the original physical device being emulated."

The save button being a floppy disk (which is no longer used), or a sheet of paper to represent a document (which may or may not ever be printed to an actual sheet of paper) are skeuomorphs by this article's defintion.

Except the save button isn't, itself, a floppy disk, it's just got a floppy disk icon on it. The floppy disk or paper iconography are not "functional input controls" themselves. They are laid upon UI chrome which is likely skeumorphic to some degree, but the icons themselves are not examples of skeuomorphism.