Models and Theories in Human-Computer Interaction/The Wiki and the Active User
A great benefit to the Wikibook is that it is great for cross collaboration across many areas and can be shareable to anyone around the world. This means there can be input from many different people across many different disciplines and can create a great resource of knowledge and power.
The Wikibook fits well into the Activity Theory because it focuses on work groups and participation, has humans anchored in the collective and adaptation, appropriation of new tools and artifacts. What that means is that the Wikibooks are created by many humans coming together. When entering and updating a Wikibook the user is sitting at their computer and most likely feels much more comfortable typing something than speaking about it in front of a group - so you get the participation, just in a more comfortable setting for a lot of users.