The strength of the wiki comes from so many eyes constantly improving it. It is the closest thing to the original concept of what the web should be – an open tool for people to share information. While abuse does exist, moderators can correct incidents.
One highly visible wiki is wikipedia, there is also wiktionary, wikiquotes, but they are well suited to collaborative projects. Organizations that are interested in knowledge management may be looking in this direction for information sharing.
For more information on wikis check out HowStuffWorks.comfor an article by Marshall Brain entitled “How Wikis Work”.