Main / Technical Aspects
Not only do wikis embody Tim Berners-Lee's vision of a read-write web, they also represent an ad-hoc form of semantic Web. As my friend Alex Bolboacă helped me realize, the average wiki naturally and implicitly supports a number of semantic relationships among articles:
In addition, PmWiki supports some unique ways to organize information, namely trails and page lists (among others). That's due to its origins in academia, but even I found uses for these features.