Recently, I came across a few interesting publishing tools:
- ShareLaTeX allows you to collaboratively edit LaTeX documents: https://www.sharelatex.com
- Anthologize is aWordPress plugin with which you can export the content of a WordPress blog as an eBook: http://anthologize.org
- Docverter is an open source server software that allows you to convert markup formats such as HTML, Markdown or LaTeX into print publishing formats like PDF or EPUB: http://www.docverter.com, source code: https://github.com/docverter/docverter
These tools should be very interesting to those who produce online content and would like to publish that content as an eBook as well without having to deal with expensive and complex DTP software or publishers.