I see many people rallying against skeuomorphism with blanket statements. They are useful but they need to be used appropriately. A general rule of thumb is if you can easily pick out the skeuomorph then it's done wrong. The page turning effect and highlighter appearance in iBooks are what I call ideal examples of great skeuomorphism. I don't think I've ever heard anyone say that needs to go and I would wager that most complaining about the faux-leather and stitching never even considered those as skeuomorphs. Notes on the iPad is a mixed bag for me with the stitching and torn paper being too much but the yellow-lined paper and the irregular red pencil mark around the current note bring a decent amount of familiarity to the functionality, even though I can see it all being cleaned in the future (example here
Originally Posted by geekdad
Nonsense! UI design IS functionality! Copy and Paste is UI functionality.......just to name one of a gazillion......swipe to unlock is UI functionality. and so on and so on.......
This can be looked at two ways. There is the first definition of functionality, which follows your comment: "the quality of being suited to serve a purpose well; practicality." That not only dictates the function is served but that a more subtle and harder to quantify aspect is also being accounted for. We've seen this for decades with people saying that Dell PCs are just as good as Macs all the way to this Android phone being better than the iPhone simply by posting some HW specs or feature without any regard for how well it actually functions for the user.
TS's usage uses a more strict and spartan definition: "the purpose that something is designed or expected to fulfill." I doubt anyone would say that good or bad UI design can not drastically add or take away from the functionality which, to me, means that it would then make good UI design something that culminate in better functionality but that is not, by design, functionality itself. Consider this scenario, you buy two doors that are exactly the same. In one you drill the holes and place the HW for the knob in the expected area; the area that a normal human being would have the best access to grab and the handle. In the other you place it 6" off the ground. The general functionality of the door is still exactly the same but one has a much more ideal method for the user to interface with it.