Directory is a technical term.
Folder was the term Macintosh/Apple coined for a visual reference to a directory back when PC was still in DOS (pre-windows).
Personally I use directory, just because I remember using DOS, which usually had Directory in a command (ie, cd stood for change directory) and VB programming uses Directory, not folder.
I too have the problem with my wife (who uses Mac), when I tell her to click on the "Denaes Directory" she has no clue and I need to correct myself "Denaes Folder".
