Dean over at Thrasherville has been chronicling the story of TOWER Software's SDK wiki, which has, as of today, returned to the fold as being available to all (and more importantly, indexed by everyone's second brain.)
The underlying principle of a wiki is that it is quick to publish. The word "Wiki-wiki", for which the modern wiki is named, means 'hurry-quick' in Hawaiian. (Not surprisingly, wikipedia has a great article on the subject...)
When you create or edit a wiki article, there are no approvals, no hoops or editors involved - any change made is immediately visible to all visitors to the site. This very feature is what makes a wiki so scary, and so extremely valuable.
You see, despite the fact that people invented bureaucracy, most people hate it. If I have to fill in a form just so, and then wait for a human to approve/edit/reject my article, chances are high that I just won't bother. Which means that everyone misses out on the knowledge I keep in my head. On the other hand, if I make it too easy to publish something, there's a risk that my valuable content could be vandalised, or plain wrong.
From a corporate perspective, having a publicly available wiki is also a double edged sword. Current and accurate information provided on demand is a must for any modern technology business - and yet misinformation, deliberate or otherwise could serve to do more harm than good. These were precisely the challenges that TOWER's management team were faced with in developing the SDK wiki. You can read more about those challenges, and how they were handled over at Dean and Paula's blog. (Although I may have spoiled the ending, I can't tell it anywhere near as well..)
Meanwhile, if you'd like to explore the world of wiki without fear of humiliation, you should check out Tiddlywiki.
Tiddlywiki is a self contained, indexed, searchable, taggable and portable personal wiki that fits in a single HTML file. You can even set up your own one-folk folksonomy!
I use it for tracking my projects, recording meetings and contacts, and it's incredibly useful.
You can download your own copy right here by right clicking this link and choosing "Save Link as".
Now that's about as quick as you can get.