JSX serializes Java objects to XML. You can persist objects, evolve them, and send them over the network and between applications. Your object data becomes human-readable and human-writable. You can test it, search it, profile it, audit it, and edit it with ordinary text and XML tools. JSX handles all POJOs and also all classes that require Java's own object serialization.
htmLawed is a PHP script that makes input text more secure, HTML standards-compliant, and suitable in general from the viewpoint of a Web-page administrator, for use in the body of HTML 4 or XHTML 1 or 1.1 documents. It is a customizable HTML/XHTML filter, processor, purifier, and sanitizer. It can ensure that HTML tags are balanced and properly nested tags, neutralize code that may be used for cross-site scripting (XSS) attacks, and limit the allowed HTML elements, tags, attributes, or URL protocols.
Bluefish is a programmer's Web development editor written using GTK, designed to save the experienced webmaster some keystrokes. It features a multiple file editor, multiple toolbars, custom menus, image and thumbnail dialogs, open from the Web, CSS dialogs, PHP, HTML, Java, C, and XML support, external program integration (tidy, weblint, make, javac), and lots of wizards.
tex-upmethodology provides a complete set of LaTeX styles that permit you to write documents according to a UP-based methodology. Its major features are document history, task management, design and specification documentation, and helping tools. tex-upmethodology is officially supported by CTAN.
Isearch is software for indexing and searching text documents. It supports full text and field based search, relevance ranked results, Boolean queries, and heterogeneous databases. It can parse many kinds of documents "out of the box," including HTML, mail folders, list digests, SGML-style tagged data, and USMARC. It can be extended to support other formats by creating descendant classes in C++ that define the document structure. It is pretty easy to customize in this way, provided that you know some C++ (and you will need to ftp the source code). A CGI interface is also included for Web based searching.
LyX is a document processor that encourages an approach to writing based on the structure of your documents, not their appearance. It is intended for people people who write and want their writing to look great without tinkering with formatting details, font attributes, or page boundaries. On screen, it looks like any word processor, but it uses the TeX engine for printed output and producing richly cross-referenced PDFs. It is stable and fully featured.