Wikipedia: The know-it-all Web site

This article provides an overview of Wiki, and explains some of the potential applications. It also touches on one of my key problems with a Wiki, which is the uncontrolled nature of the content editing. While that doesn't mean that it will be necessarily be abused, it is open to abuse. And if you have to manage a Wiki and rollback to previous versions of content to correct for this problem, it makes me question the use of the technology at all. Why not use community blogs?