Just wanted to draw attention to Booktype (AGPLv3), software for collaborative book writing. Perhaps of interest for FreedomBox in the future.
With Booktype you can create books. Real, good-looking paper books you can hold in your hands. You can also use Booktype’s output to PDF, EPUB, XML and HTML to export books ready for Amazon, iBooks, or the open web. [from: http://sourcefabric.booktype.pro/booktype-23-for-authors-and-publishers/what-is-booktype/]