Here's an experiment we are running here for our technical documents. We have an Etherpad server (http://etherpad.org/ http://etherpad.org/) we heavily use, an

Here's an experiment we are running here for our technical documents. We have an Etherpad server (http://etherpad.org/ http://etherpad.org/) we heavily use, and we've used it to write some of our technical docs in Markdown. We use other pads to define HTML templates. Then, we have simple web app which merges a chosen HTML template with the Markdown content, which lets the user preview the rendered results before saving the final HTML output. Advantages: you get all Etherpad's realtime collaboration goodness, automatic version control and revision history, the HTML templates can be edited simply (and restricted to editing by certain users), it's pretty quick to pick up. Disadvantages: Etherpad is primarily text based so you're SOL if you need diagrams etc, slight complexity of the parts (templates, content, web app) to make it run.