SDoP (Simple DocBook Processor) reads a DocBook XML file, processes it into typeset pages, and outputs the result as PostScript (which can easily be converted to a PDF). It is "simple" because it supports only a subset of DocBook, and also because it does not make use of a DTD or stylesheets or any other heavyweight apparatus. It is a single program. SDoP is used to format the Exim reference manual.
DokuWiki is a standards-compliant, simple-to-use Wiki mainly aimed at creating documentation of any kind. It is targeted at developer teams, workgroups, and small companies. It has a simple but powerful syntax which makes sure the datafiles remain readable outside the Wiki, and eases the creation of structured texts. All data is stored in plain text files, so no database is needed
The DocBook Authoring and Publishing Suite (DAPS) provides a tool set for easy creation and publication of DocBook sources on Linux. It lets you create HTML (including Webhelp), PDF, EPUB, man pages, and other formats with a single command. It automatically takes care of validating and filtering (profiling) your sources and automatically converts images into a format best suited for the output format. You can easily create profiled source tarballs for translation or review. DAPS supports authors by providing linkchecker, validator, spellchecker, and editor macros. It is well suited to manage large documentation projects with multiple authors using the DAPS docmanager.
SimplyBibTeX is an application to share and hold BibTeX bibliographies. One can add, edit and remove entries from bibliographies online or upload complete collections. The system uses a very simple but effective template mechanism. Users and coworkers can subscribe to RSS 2.0 or Atom feeds in order to get notified about changes.
Txt2tags converts a text file with minimal markup to HTML, XHTML, SGML, DocBook, LaTeX, Lout, Man page, Creole, Wikipedia, Google Code Wiki, PmWiki, DokuWiki, MoinMoin, MagicPoint, PageMaker, AsciiDoc, or ASCII Art. It is simple and fast and features automatic TOC, macros, filters, include, tools, GUI, CLI, and Web interfaces, translations, and extensive documentation.