A Wiki is a linked set of pages that anybody can edit and contribute to without knowing anything about websites. Wikipedia is the prime example of a successful wiki project. Also, check out Why Wiki Works for some information on the philosophy of wiki.
If you see something you think is inaccurate or incorrect, you have the power to change it.
If you see that something is incomplete, you can add more information.
If you think someone missed the point or slacked off, you can add to the information on a page.
You can use the wiki as a forum for discussion on a topic.