The structure of wikis is interesting. How are the page inter-linked? There is an example in http://seattlewireless.net/index.cgi/HowDoesThisWikiLookLike. The number of links per page (references to other pages or references from other pages) seems to follow a PowerLaw distribution.
There are more examples (in French) on http://reseaucitoyen.be/index.php?TopologieDuWiki.
with the references counts distribution like this :