I've figured it out: the stuff on your iPod that shows up in iTunes can't be copied off it.

But, when you're connected to your computer, there's an icon on the desktop that opens to a normal Finder window (that's in Mac-speak: presumably something similar happens on a PC -- a regular file directory window can be opened.). Different folders (Calendar, Contacts, Notes, Recordings) show up there than appear in iTunes, and the Music, Video, etc. that you see in iTunes are invisible.

I can copy a text file from my computer to the "Notes" folder in the Finder window, and then copy it back with no problem. I can also view the text on the iPod screen (although I can't figure out how to increase the font size...).

So, that's where the other sorts of data go.

There are of course various utilities available (not from Apple) for downloading the downloadable stuff, easily found via Google.

~ Becky in Tucson