Check out this interview with Dru Lavigne by, the one behind FreeNAS and PC-BSD documentation. She discusses their switch to using Sphinx, an open source doc system. See the full interview in the link below.

Why did the PC-BSD, FreeNAS, and Lumina documentation projects move to Sphinx?

When I became responsible for the maintenance of the PC-BSD documentation back in 2010, I inherited an existing documentation wiki that contained a lot of user-generated content, most of which was several years out of date. Shortly thereafter, I also became responsible for creating the new FreeNAS documentation, so it made sense to also make a documentation wiki for that project.

Over time, the shortcomings of the wiki approach for maintaining updated and versioned documentation became apparent: …

Full interview: