I've been thinking for a while that I don't quite like directories, as
organizing metadata.  Too restrictive: you can only really choose one place,
to find something you already have to know where to look (or search through
everything), and if you choose long, comprehensible names, your unique set
of metadata to find a file becomes very long.

Consider, by contrast, a service like Evernote.com (KPhotoAlbum also does
tags well, and delicious.com for web pages).  It has folders, yes, but
what's better is that it lets you assign keywords to the note (really just
arbitrary textual (or other) data).  The note's topic is in essence the
combination of all the keywords, so if you are interested in one of those
keywords in the future, looking for the keyword (or some combination of
keywords) would list all the notes with those keywords attached.

I think the latter approach would produce a more usable, less frustrating
filesystem than the former.

Jason Catena