Here's an interesting idea from Justin Chapweske: Wiki + WebDAV = WikiFolders:

The basic idea behind WikiFolders is to ditch hierchical file organization in favor of the ad-hoc approach of Wikis. Instead of a hierchical organization of folders and files, we change the file system semantics to that of linkages between wiki pages and optional file attachments.

All folders in the file system would be WikiWords and likewise, all WikiWords within a wiki page would show up as a folder in the file system.