The term “wiki” comes from the Hawaiian phrase, “wiki wiki,” which means “super fast.” A wiki is a server program that allows users to collaborate in forming the content of a Web site. With a wiki, any user can edit the site content, including other users’ contributions, using a regular Web browser. Basically, a wiki Web site operates on a principle of collaborative trust.
If you can spare about 4 mins – the video below will clue you in to the basics.
The best known wiki is Wikipedia the free on-line encyclopedia.
Most wikis have a “history” feature so that you can compare versions of the article. By looking at the Wikipedia history of a major event e.g. a Terrorist attack you can basically see our understanding of history unfolding. This confirms that History is only obvious in retrospect.
Wikis are also increasingly being used by business and not for profit organisations for planning.