I found that for me, there is actually a second idea in the Wiki Os discussion here which is better named Os Wiki.
A crunchy breakfast treat. Won't get soggy in milk, and if you don't like the flavor you can change it yourself!
Haha! I just snarfed my Wiki Os when I read that!
Much of the power of Unix stems from its ubiquitous hierarchically structured file system. We think that it might be beneficial to get away from the "file and folder" metaphor for organizing information - a Wiki would enable a much more powerful basic metaphor for an OS, heavily cross-linked and easily changeable by the user. In the extreme, it could be as simple as a desktop wrapper layer on top of an existing OS, see Wiki Active Desktop.
The "file and folder" metaphor for organizing information doesn't really correlate to real life. Moreover, people are more comfortable dealing with "things" and not streams. So it's possible for an object-oriented storage system to be simpler to use.
And who says hierarchical filesystems scale? Either having too deep directory structures or too many files in a directory makes finding things a pain. It certainly is fine if you don't have a lot of files, but as the number grows... just try to make sense of the \windows and \windows\system directories, for example, or the mess of directories Linux can have.
You can have an hierarchical structure in an object repository too, implemented with Composite Pattern, for example. As objects can have pointers to other objects you get hyperlinks. But the idea seems to be a filesystem where you can have links from a file to other files as easy as links among pages here in Wiki, and of course navigation to previous links (your browser's Back button), categories, search... only instead of pages you'd have files (or objects).
Wiki Os-like implementations
Microsoft Cairo went in that direction, but it died.
There's a project on www.sourceforge.net 
that aims to build a Squeak Smalltalk VM that can run without an OS, Squeak itself would be the OS.
A possibly superior alternative to filesystems is checkpointing, as done by Eros Os:
www.eros-os.org In Eros, there's no file system. All data is just a pointer dereference away; the virtual memory system "checkpoints" the whole address space every 5 minutes or so. So if your computer crashes, you never lose more than 5 minutes work. The user doesn't have to bother with low-level concepts like "saving" and "loading" files.
Some very interesting papers about Lifestreams and organising files in a different way:
www.cs.yale.edu , etc.
[Contributors: Ralf Mueller, Uwe Franke, Sunir Shah, Falk Bruegmann, Fabio Mascarenhas, Peter Schaefer]
This is continued in Thread Mode in Wiki Os Discussion, Os Wiki.
See original on c2.com