Blog, Wiki, or CMS: Choosing a Platform for Your Project

My experience has been primarily with WordPress, MediaWiki, and Drupal. Each has a different set of features and constraints so how do you decide whether you need blog, wiki, or CMS? Not everything is bloggish, although there are times when blogging software can make an excellent lightweight CMS. Sometimes you need something a little heavier, and sometimes the collaborative style of a wiki is best. I'll share my experiences with WordPress, MediaWiki, and Drupal including what has worked well and what things have been problematic.