What's a Wiki?
So far, I think this page gives the quickest and best introduction to it all:
Wiki Wiki is the Hawaiian term for "quick". Ward Cunningham is the one who coined the phrase of "Wiki Wiki Webs" (not to be confused with Will Smith's "Wiki Wiki Wild Wide Web"). The idea is that you edit pages using simple formatting rules, and the references between pages are maintained automatically when hyperlinks are created.
It all works via CGI on a web server, so anyone with a web browser anywhere in the world can browse, follow links, and edit these pages.
For a few links to Wiki stuff, look at http://c2.com/cgi/wiki?WikiWikiWeb
A list of implementations of Wiki webs is at http://c2.com/cgi/wiki?WikiWikiClones
There is an internal project at Xerox Parc called "Sparrow" , which adds a fascinating new dimension to Wiki, by allowing users to edit portions of a standard HTML page:
SlashDot has had a similar concept for some time with Everything , but implemented as a sort of learning network, with the "strength" of links dependent on how often they're traversed.