phpList
phplist is an open-source newsletter manager. A feature-rich mailing script, which includes multiple mailing lists and attachments. phplist is free to install and use, and is easy to integrate with any website. phplist is listed in the top open source projects for vitality score.

Movable Type
With more than 50 new features, MT4 will enable you to quickly start a blog, easily manage entire blogging websites, and better connect with your audience. Here's some of what's new in MT4: A completely redesigned user interface It’s easy to install and easy to get started. Get an at-a-glance summary of your blogging activity from content to contributors on our new dashboard. Easily insert text, photos, files and more with a rich WYSIWYG editing.  Built-in asset, photo and file management. Support for creating standalone pages that automatically inherit your blog's design. Built-in member registration system for reader and comment authentication. Support for OpenID. Aggregate posts from multiple blogs into a single blog. Expanded options for archiving and displaying content.

Textpattern
When it comes to publishing on the internet, beginners and experts alike are met with a bothersome paradox: word processors and graphics applications allow anyone to do a pretty good job of managing text and images on a personal computer, but to make these available to the worldwide web  a seemingly similar environment of documents and destinations  ease of use vanishes behind sudden requirements for multilingual programming skills, proficiency in computer-based graphic design, and, ultimately, the patience of a saint. Those who soldier on anyway may find themselves further held back by the web’s purported inflexibility with written language, with its reluctance to cope with all but the plainest of text, or by the unpredictable results brought about by using WYSIWYG  web editors. Textpattern is a web application designed to help overcome these and other hurdles to publishing.

WordPress
WorldPress is a personal publishing script, which offers a cross-blog tool, password-protected posts, importing, typographical eye candy, Multiple Authors and Bookmarklets.

b2evolution
b2evolution is a powerful blog tool you can install on your own website. It includes all the features of traditional blog tools, and extends them with evolved features such as file & photo management, advanced skinning, multiple blogs support as well as detailed user permissions... Not to mention third party plug-ins!

Drupal
Drupal is an advanced open-source content management tool for creating dynamic websites, which provides a broad range of features and services such as: user administration, publishing workflow, discussion capabilities, news aggregation, metadata functionalities using controlled vocabularies and XML publishing for content sharing purposes.

Geeklog
Geeklog is a weblog powered by PHP and MySQL. It allows you within minutes to set up a fully functioning dynamic website, and has many features to get you started.  It provides you with user-system, allowing members of the public to register for your site and submit stories. Also it have a comment system, allowing users to comment on posts made to your site.  Using the Block system, you can put information anywhere on your site. The Plugin system allows you to extend Geeklog, without having to code any new PHP.  The Theme system allows the users to select what layout they want to view.

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 applications. Joomla! is easy to install, simple to manage, and reliable. Joomla! is used all over the world to power everything from simple, personal homepages to complex corporate web applications.

Mambo
Mambo is a dynamic Web content management tool that is capable of building sites from several pages to several thousand. It is a full-featured content management system that can be used for everything from simple websites to complex corporate applications. Continue reading for a detailed feature list. Mambo comes complete with 10 built-in modules, a WYSIWYG editor, site statistics, an admin interface, multi language support, custom module support, and more.

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.

Nucleus
Nucleus is a Content Management System (CMS): a powerful set of PHP scripts that allow you to maintain one or more weblogs or online journals. A powerful blog script featuring multiple blogs, multiple authors, drafts and future posts, bookmarklets. Nucleus is far more flexible and powerful than most of the CMS scripts, it expresses the values that guided its birth: flexibility, security, and computational elegance.

Open Realty
Open-Realty is free web based listing management application for real estate websites for real estate websites. It is intended to be both easy to setup and use. Written in PHP, Open-Realty is designed to be a fast and flexible tool for your website. With a large open-source community working with this application, and solid management from Transparent Technologies open-realty is the top choice for use on your website.

WebSiteBaker
Website Baker is a PHP-based Content Management System (CMS) designed with one goal in mind: to enable it's users to produce websites with ease. This Website Baker "Start" website is a resource for people wanting to find out more about Website Baker, and get a "start" with the project and our community.

fuzzylime (cms)
fuzzylime (cms) is the easiest way for you to run your site and keep it up-to-date. Once installed, you can update from any internet-connected PC in the world - you don't even need to know HTML! It has tons of features so whatever you want from your site; chances are this script will be able to do it for you.

php-fusion
PHP-Fusion - a light-weight open-source content management system (CMS) written in PHP. It utilises a mySQL database to store your site content and includes a simple, comprehensive adminstration system. PHP-Fusion includes the most common features you would expect to see in many other CMS packages.

phpWebSite
phpWebSite provides a complete web site content management system. Web-based administration allows for easy maintenance of interactive, community-driven web sites. phpWebSite's growing number of modules allow for easy site customization without the need for unwanted or unused features. Client output from phpWebSite is valid XHTML 1.0 and meets the W3C's Web Accessibility Initiative requirements. phpWebSite allows an individual or group to easily maintain an interactive, community-driven web site.

xoops
XOOPS is an extensible, OO (Object Oriented), easy to use dynamic web content management system written in PHP. XOOPS is the ideal tool for developing small to large dynamic community websites, intra company portals, corporate portals, weblogs and much more.

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.

PHPTickets
phpTickets is a trouble ticket support system written in PHP and utilizes a mySQL databse for storage. Tickets can be entered manually or can also be pulled in automatically from any POP account. Each new ticket is assigned a unique number and is tracked and replied to via this tracking number. This makes trouble ticket reporting easier to maintain tickets throughout their life cycle until they are closed.

phpBB2
Since its inception, phpBB has been among the leading bulletin board solutions and quickly rose to be the world's leading Open Source forum software. phpBB has always comprised of a key feature set, including powerful permission systems, private messaging, search functions, a customisable template and language system, as well as support for multiple databases.

Simple Machines Forum - SMF
Simple Machines Forum - SMF in short - is a free, professional grade software package that allows you to set up your own online community within minutes.

OS CommRes
OS CommRes ranks first among the most powerful open-source booking systems. The commercial solution is based on the secure, scaleable and reliable OS CommRes project. The solution includes a full Call Centre module, and key metrics such as inventory management, sales auditing, and bookings analysis.

OS Commerce
osCommerce is an online shop e-commerce solution that offers a wide range of out-of-the-box features that allows online stores to be setup fairly quickly with ease, and is available for free as an Open Source based solution.

DOTproject
dotProject is a web-based project management application, designed to provide project layout and control functions.

PHProject
PHProjekt is a modular application for the coordination of group activities and to share informations and document via the web. Components of PHProjekt: Group calendar, project management, time card system, file management, contact manager, mail client and many other modules.

MJguest
MJGUEST is a free professional guestbook, designed as hi-end solution for both personal homepages and corporate websites.

4Images Gallery
4images is a powerful web-based image gallery management system. Features include comment system, user registration and management, password protected administration area with browser-based upload and HTML templates for page layout and design.

Coppermine
Coppermine Photo Gallery is an advanced, user-friendly, picture gallery script with built-in support for other multi-media/data files. The gallery can be private, accessible to registered users only, and/or open to all visitors to your site. Users, if permitted, can upload pictures with their web browser (thumbnail and intermediate sized images are created on the fly), rate pictures, add comments and even send e-cards. The site administrator determines which of the features listed above are accessible by registered and non-registered users.

Gallery2
Gallery is a web based software product that lets you manage your photos on your own website. You must have your own website with PHP and database support in order to install and use it. With Gallery you can easily create and maintain albums of photos via an intuitive interface. Photo management includes automatic thumbnail creation, image resizing, rotation, ordering, captioning, searching and more. Albums and photos can have view, edit, delete and other permissions per individual authenticated user for an additional level of privacy.

plogger
Plogger is the next generation in open-source photo gallery systems. A web application not bloated with superfluous features or complicated configuration settings. Plogger is a simple yet powerful tool - everything you need to share your images with the world. Plogger is your photos integrated into your website, a fully featured photo sharing package with an attractive and easy to use administrative interface that makes managing your galleries a breeze. Integrating our gallery software into your website is as easy as inserting three lines of PHP code.

phpcoin
phpcoin is a comprehensive billing/invoicing application, perfect for web hosting resellers to manage their customer orders, invoices, notes and helpdesk. The tool can be used by different types of businesses as well.

DokuWiki
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 no database is required.