Wiki Wiki Web
A Wiki is a tiny Hawaiian bus used to shuttle tourists around. And to WikiWiki is to shuttle back and forth amongst pages in a WikiWikiWeb.
A Wiki Web is a collaborative tool for having semi-permanent discussions about a variety of topics. It is an electronic blackboard of sorts with a few more features:
The contents are global... Well visible from any computer with a modern browser on it. It has hyperlinks... You can create a jump from one page to another in a very simple way. see TextFormattingRules? and HelpPage? The pages are versioned... just in case someone wipes an important piece of information away.
HowToWikiWiki shows some quick start things you can try right away.