!!! Wiki as filesystem
There have been some nice experiments to make a wiki behave more like a filesystem:
*[Integration of webdav and JSPWiki|http://codinginparadise.org/weblog/2004/08/i-added-webdav-to-open-source-wikiwiki.html]
*[FUSE filesystem for mediawiki|http://wikipediafs.sourceforge.net]

[FUSE|http://fuse.sourceforge.net/] is a promising technology available on most *nix platforms (works on [MacOS X|http://code.google.com/p/macfuse/], Linux, FreeBSD, [OpenSolaris|http://hub.opensolaris.org/bin/view/Project+fuse/]) 

There quite a few obstacles in the way of a seamless solution:
* Windows seems to have made webdav optional
* Firefox does not know how to handle dav protocol and Gnome does not allow to follow the links if the webdav is not already mounted.

!!! Wiki as web hosting solution
It would be useful to be able to just add a bunch of html files on a wiki and have it host them. For instance and zip file could be attached and a special URL could be used to access the contents of the zip file with names such that local hyperlinks of the contents would work.

!!! Storage filesystem

The Wiki needs a filesystem to store its pages and attachments. JSPWiki uses the plain filesystem to do that and does versioning itself (although Emforge does it with subversion).