> Watch any nontechnical person using Windows or the Mac.
Yes. I have observed that for almost 15 years. People cannot find a file unless it is on Desktop. This has become worse with recent tendency to use Downloads or similar folder by default to save files.
What is interesting is that many people seems just remember the location of the file on desktop and if the icons is rearranged they have some hard time initially. For those people the button that MS have added in Windows 98 (or something) to show the desktop was a real productivity boost and so was the ability to drag files from the desktop to open them in applications (like mail attachments etc.)
Yet it seems all those modern interfaces do not try to explore that tagging by visual location on the screen.