The Wiki Way: Quick Collaboration on the Web by Bo Leuf and Ward Cunningham.
Been looking for this book for quite a while now. As with Hidden Connections, I found it at a used bookstore today.
I first encountered the wiki way on Wikipedia.org, where anyone--even me--can edit and add articles. I started a few stubs, enjoyed watching them evolve, even when my precious writing was updated. Almost always, the evolution of the articles made them better. Of course there comes a point of diminishing returns.
So I played with installing various wikis, including Wikimedia (wikipedia's engine) and PmWiki, the PHP script running this wiki. Wikimedia was a monster. Huge resource hog, database driven. PmWiki was relatively resource light, no database, flat file, which at first I disliked, but as I read the developer's reasons for choosing flat file, I bought into the idea. In fact, I've become very enthusiastic, in large part because updates are a breeze. I have a Drupal blog that is MySQL driven, and version updates are a nightmare--mostly because of the damn database.