Users with many CDRs and who forget where everything is.
Users who have a lot of music files and they need a way to find a specific
file and play it easily, especially with the case of wav, midi, mp3,...
Users who download a lot of image from the internet and they forget what
each image is, so they can have notes attached to each image file, and then
later on you can search through the comments.
Users who do a lot of photo images, and they need a way to classify their
files.
Users who download files from the internet and they need to keep track of
what the file is, where they got it from and what version it is.
Users who have a lot of document files, spanning many disks and they need
fast ways to locate specific documents.
Users who have lots of games and they need an overview of where everything
is.