phpBB2: A widely-popular open-source bulletin-board package, works well, simple user interface and admin panel, clean look, scales well, and can be customized.

4Images Gallery: An Image Gallery system featuring unlimited categories/subcategories, web-based and FTP images upload, auto-thumbnails, comments, send a picture, rate a picture, random pictures, extensive administration panel.

Coppermine: An Image Gallery system featuring categories and albums, thumbnails and intermediate size pics, search feature, new and random pictures, user management (private galleries, groups), user comments, e-cards feature, slideshow viewer.

b2evoltion: A blog script featuring multiple blogs, categories/sub-categories, skins, search function, multiple languages, search engines friendly URLs.

Crafty Syntax Live Help: A Live Help chat system featuring monitor your visitors, proactively open a chat session, multiple chat sessions, referrer tracking, page view tracking, multiple operators, canned responses/images/URLs, multiple departments each with different icons, leave a message.

dotProject: Project Management featuring companies, projects, tasks (with Gantt charts), forums, files, calendar, contacts, tickets/helpdesk, language support, user/module permissions, themes.

Drupal: An advanced portal with collaborative book, search engines friendly URLs, online help, roles, full content search, site watching, threaded comments, version control, blogging, news aggregator.

FAQ MasterFlex: Unlimited categories/questions/answers, web-based administration.

GeekLog: A portal system with a wide range of modules.

Help Center Live: Very powerful all-in-one help center including Live Help, Support Tickets and FAQ. Features include unlimited operators/departments, monitor visitors, initiate chat, collect visitor's information, track visitor's footprint, autosave chat transcripts, canned messages, leave a message, auto-assign tickets to operators, unlimited FAQ topics.

Joomla: Joomla! is one of the most powerful Open Source Content Management Systems on the planet. It is used all over the world for everything from simple websites to complex corporate applacations. Joomla! is easy to install, simple to manage, and reliable.

Mambo Open Source: A professional level yet easy to use Content Management System featuring inline WYSIWYG content editors, newsfeeds, syndicated news, banners, mailing users, links manager, statistics, content archiving, date based content, 20 languages, modules and components.

Moodle: A course management system designed to help educators create quality online courses. Available in 34 languages and features a WYSIWYG HTML editor. The teacher has full control over all settings for a course. There is a flexible array of course activities (Forums, Journals, Quizzes, Resources, Choices, Surveys, Assignments, Chats, Workshops), user logging and tracking, mail integration and much more.

Noah's Classifieds: A classifieds system featuring categories and subcategories in unlimited depth, image upload for categories and classifieds, variable fields per categories, customizable email notifications, locking categories, classifieds approval, auto-thumbnail generation, classifieds management by user, send classified to a friend.

Open Realty: Real Estate listing system featuring attachments, flexible search, template system, Yahoo Maps interface.

osCommerce: A power-user shopping cart with a big variety of modules and support of almost every payment gateway. A big developers community is ready to offer custom solutions depending on your needs.

osTicket: A Support Tickets system featuring email piping, pop3 login, unlimited email addresses, admin/staff/user panels, avoid autoresponder loops, limit maximun tickets user can have opened, accept attachments and limit size, pager alerts for admin.

Nucleus: A powerful blog script featuring multiple blogs, multiple authors, drafts and future posts, bookmarklets.

Perldesk: PerlDesk is a feature packed browser based help desk and email management application designed to streamline the operation of managing emails, support tickets and customer comminications, with built in tracking and response logging it is an ideal help desk solution for companies with one or more members of staff or for those who want to organise client communications.

phpAdsNew: A highly professional complete ad server featuring different types of ads, display based on keywords, zones, hour of the day, day of the week, extensive statistics, client statistics.

PHPauction: The GPL version of PHPauction featuring email notification of bids, attachments, reserve price, minimum bids, standard and dutch auctions, bid history, send auction to a friend, highest bids, auctions ending soon.

phpESP: PhpESP is an effective, capable, web-based survey application that enables businesses to create complex and advanced surveys, view results in real time, and carry out advanced analysis.

php Form Generator: A form generator featuring up to 100 form fields, all kind of input fields incl. file upload, customizable fields attributes, send submitted data to an email address or store them in a database, admin panel.

PHP List: A powerful mailing list featuring multiple mailing lists and attachments.

phpNUKE: One of the most popular community-based portals with a big choice of modules and languages.

PHPProjekt: Project Management featuring optional group system, privileges, calendar, contacts, time card, projects, chat, forum, request tracker, mail client, files, notes, bookmarks, to-do list, reminder, voting, language support.

PHPSurveyor: Develop, publish and collect responses to surveys. Display surveys as single questions, group by group or all in one page or use a dataentry system for administration of paper-based versions of the survey. PHP Surveyor can produce 'branching' surveys (set conditions on whether individual questions will display), can vary the look and feel of your survey through a templating system, and can provide basic statistical analysis of your survey results.

PHPWCMS: phpWCMS is perfect for professional, public and private users. It is very easy to learn and gives you the flexibility to separate layout and content. Lots of powerful but simple implemented features assists publishers and web developers too.

phpwebsite: Very powerful Content Management System with document manager, announcements, menu manager, photo album, block maker, FAQ, web pages maker, polls, information categorizer, calendar, link manager, form generator.

phpwiki: PhpWiki is a web site where anyone can edit the pages through an HTML form. Linking is done automatically on the server side; all pages are stored in a database.

pMachine: This is a features limited version of pMachinePro.

postnuke: A Content Management System with focus on flexibility and security. A big variety of modules and blocks makes this CMS an allround tool.

Siteframe: A straightforward content-management system designed for rapid deployment of community-based websites. Nice-looking templates, oriented toward document-sharing, clean interface.

Support Logic: A Support Tickets system featuring multiple email addresses, admin/staff/user panels, canned responses, HTML tags support, email limit on a per user/day basis, attachments.

Support Service Manager: Support System

Tikiwiki: TikiWiki is designed to be an international, clean and extensible Content Management System and Groupware that can be used to create all sorts of web applications, sites, portals, intranets and extranets. TikiWiki also works great as a web-based collaboration tool. TikiWiki has a lot of native options and sections that you can enable/disable as you need them.

TYPO3: TYPO3 is a free Open Source content management system for enterprise purposes on the web and in intranets. It offers full flexibility and extendability while featuring an accomplished set of ready-made interfaces, functions and modules.

WebCalendar: A very powerful webcalendar featuring private and public calendars.

WordPress: WordPress is a personal publishing tool with focus on aesthetics and featuring cross-blog tool, password protected posts, importing, typographical niceties, multiple authors, bookmarklets.

Xoops: A very popular advanced portal system.

Zen Cart:Zen Cart truly is the art of e-commerce; a free, user-friendly, open source shopping cart system. The software is being developed by group of like-minded shop owners, programmers, designers, and consultants that think e-commerce could be and should be done differently.