GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
gjots lets you organize text notes in a convenient, hierarchical way. It can be used for notes, jottings, bits and pieces, recipes, and even PINs and passwords, using encryption. It can also be used to "mind-map" larger compositions like manuals, Web pages, articles, etc. It is a bit like the KDE program "kjots", but uses the GTK library and supports a hierarchy of folders. Files can be output to HTML with an automatic table of contents or to docbook XML. Encryption is supported with ccrypt(1), gpg(1), and openssl(1), so that musings can be kept private.
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 goal of Hilbert II, which is in the tradition of Hilbert's program, is the creation of a system that enables a working mathematician to put theorems and proofs (in the formal language of predicate calculus) into it. These proofs are automatically verified by a proof checker. Because this system is not centrally administered and enables references to any location on the Internet, a world wide mathematical knowledge base could be built. It also contains information in "common mathematical language".
bib2xhtml is a program that converts BibTeX files into HTML (specifically, XHTML 1.0). The conversion is mostly done by specialized BibTeX style files, derived from a converted bibliography style template. This ensures that the original BibTeX styles are faithfully reproduced. Some post-processing is performed by Perl code. This is an update of the bib2html program written by David Hull in 1996 and maintained by him until 1998.
deplate converts wiki-like markup to LaTeX (standard classes, koma, dramatist, sweave), HTML/PHP (single page, chunked/website, HTML, or s5-based slideshow), DocBook (article, book, man/ref page), and really plain text. Currently supported input formats are viki and Ruby's rdoc. The viki markup supports footnotes, citations, index, table of contents, embedded LaTeX for mathematics, integration with R for dynamically generated figures and tables, and more. Output can be customized via page templates.
xhtml2pdf converts HTML/XHTML/XHML to PDF using the ReportLab Toolkit, the HTML5lib, and pyPdf. It supports HTML 5 and CSS 2.1 (and some of CSS 3). The main benefit of this tool that a user with Web skills like HTML and CSS is able to generate PDF templates very quickly without learning new technologies.
Kiwi is yet another text to HTML processor which was designed for writing small and medium technical documents and notes. Its markup is very close to the Markdown markup, but Kiwi allows more flexibility in the presentation of your documents. Kiwi is good for writing technical documents, taking notes, or as an engine to be embedded in your application. It has rather complete API documentation.
Rextile allows you to build XHTML documents and entire Web sites with ease. You write text using Textile (a format much more concise than XHTML), automate document parts with Ruby scripting, and generate the site offline (the server gets static XHTML). Rextile was inspired by Xilize. It uses RedCloth to convert Textile to XHTML, erb to run script blocks, and Hpricot for DOM manipulation.