Relating to some research that we're doing surrounding the generation of content, both for our own website and for others, I've been thinking about the question of how to create collaboratively create content in a way that allows both ease of use (for non-technical users), while at the same time allowing for advanced editing functions by more technical users, such as the use of structured markup and authority identifiers.
I stumbled on Connexions, an open-source plone-based system developed by Rice University, and used by them to collaboratively create educational and academic content.
Connexions allows for creation of XML-based content, as well as importing from other formats such as Word, and appears to have a nice collaborative environment.
Where this gets interesting is that Rice University Press have in recent times re-invented themselves as a fully digital publisher, producing print-on-demand books using the Connexions system.
They claim that, using Connexions to create the digital content and then partnering with an on-demand printing service, they can create peer-reviewed academic publications for a tenth the cost using the traditional model of a University Press.
As Connexions is open-source, it is also downloadable for use by others.