Swiki (Simple Wiki, or SqueakWiki, or even, Stupid Wiki) is an implementation (perhaps, interpretation) of Wiki implemented in Squeak on top of the PluggableWebServer by MarkGuzdial. Swiki is an example included with the PluggableWebServer..
Description of Swiki and the PluggableWebServer are available at http://pbl.cc.gatech.edu/myswiki/1. (archive.org: https://web.archive.org/web/20041019094847/http://pbl.cc.gatech.edu/myswiki/1 )
Swiki now has a 'younger, more muscular little brother' - Comanche. Information is available at the site above, or at http://wiki.squeak.org/swiki/ or at http://www.frivschool.org There is also another Simple Wiki written in FreePascal is located here: http://z505.com/cgi-bin/wik/wik?p=main-page