BitNami Tracks Stack is an all-in-one cross-platform installer for Tracks, a Web-based application to help you implement David Allen's Getting Things Done methodology. It installs Tracks, Ruby On Rails, and everything else necessary to have a running program in minutes. It works on Windows, Linux, and OS X.
BitNami Roller stack is an easy to install distribution of the Roller blogging software. It includes preconfigured, ready to run versions of Tomcat and MySQL, so users can get a Roller install up and running in minutes after answering a few questions. Currently, Linux, Windows, and Mac OS X are supported.
PyleWiki is a WikiClone written entirely in Python that allows a group of people to collaboratively edit a tree of webpages using nothing but their browser and a simple, text-based markup language. This particular WikiClone has a few extensions to the original: attachments to pages, user authentication (primitive), and the use of templates for page styling among others.
RSSOwl is a wise SWT-based news aggregator. Its search feature lets you hunt down the best RSS/RDF/Atom feeds on the Web, and then organize and share your feeds with agility. Other features include an integrated browser; AmphetaRate, for acquiring news tailored to your tastes; full-text searching through headlines and descriptions; export feed summaries to PDF, RTF, and HTML; the ability to import or export OPML; the ability to exchange collections with others by importing or exporting subscriptions; the ability to import or export user data to and from other machines; automatic newsfeed upating; and much more.
Drivel is a GNOME client for working with online journals, also known as weblogs or simply blogs. It retains a simple and elegant design while providing many powerful features, including support for LiveJournal, Blogger, MovableType, Advogato, and Atom journals. (Systems based off these are also supported, including WordPress and Drupal.)