. . . or at least I think that's what you should call it.
As I am downloading all my music on CDs I have come to a bit of a dilemma on how to categorize the music. Do you I go by genre? Artist? Era? Favorites? Tagging has resolved some of this dilemma as you can identify an article with several tags (Tagging is currently not available on Windows so that doesn't help me); however, there is no structure around it. I think that solution is limited because it looses the tree structure of a filing system or groupings. My solution: Dynamic Directory.
I, the user, would define a tree structure of how I want my folder (tag) directory should be, and through those paths, I could get to the same articles without having duplicate articles.
So, for example, at Level 1, I could have Genre, Era, Band.
Genre could then go: Genre > Band > Song or Genre > Era > Band > Song or Genre > Band, Era > [Band > Song], [Era > Song]
You get the idea. By the tagging of the article and defining my tree structure, I could navigate through my groupings as I see appropriate and still reach articles that should be within those groups (tags), even if they are in multiple groups.
This concept could be applied to any application which requires directory structures.
Addendum:
Actually, now that I think about it, as long as you define the next-to relationship and the Level 1 tags, the directory structure could create itself, rather than you defining the paths. The user could have the flexibility to define multiple next-to relationships on one tag.