Collaboration Platform

Plone is easy to use. The Plone Team includes usability experts who have made Plone easy and attractive for content managers to add, update, and maintain content.
Plone is easy to install. You can install Plone with a click-and-run installer, and have a content management system running on your computer in just a few minutes.
Plone is international. The Plone interface has been translated into over 30 languages, and tools exist for managing multilingual content.
Plone is standard. Plone carefully follows standards for usability and accessibility. Plone pages are compliant with US Section 508, and the W3C's AA rating for accessibility, in addition to using best-practice web standards like XHTML and CSS.
Plone is Open Source. Plone is licensed under the GNU General Public License, the same license Linux uses. This gives you the right to use Plone without a license fee, and to improve upon the product.
Plone is supported. There are close to a hundred developers in the Plone Development Team around the world, and a multitude of companies specializing in Plone development and support.
Plone is extensible. There are many add-on products for Plone that add new features and content types. In addition, Plone can be scripted using web standard solutions and Open Source languages.
Plone is technology neutral. Plone can interoperate with most relational database systems, open source and commercial, and runs on a vast array of platforms, including Linux, Windows, Mac OS X, Solaris and BSD.

An integrated web content management and corporate portal server; 100% Java based; Available under a collaborative source license (contribue or pay paradigm); Installed in minutes; Easy to use and to administer; Full Multilanguage and I18N support; Staging environement (Draft & Preview mode); Content Workflow; Content Versioning; Document Management (WebDAV Support); Built-in Portlet-based interface; Built-in support for standardized java web applications and web services (default servlets supported as portlets); Full web-based administration; Integrated with the Apache Lucene Search Engin

DotNetNuke is an Open Source hybrid of the IBuySpy Portal. Its management team is dedicated to the ongoing management of core portal application enhancements. DotNetNuke provides automated content management capabilities and tools to maintain a dynamic and 100% interactive data-driven web site.

Alfresco is the first open source enterprise-scale document management system that includes a modern content repository, an out-of-the-box portal framework for managing and using content designed to work with standard portals, and a groundbreaking Common Internet File System (CIFS) interface that provides Microsoft Windows file system compatibility. Alfresco takes the lessons of building document management systems for the last 15 years and applied them to build an open source content management system that is easier to use, more scalable and more adaptable.

MindTouch Deki Wiki is a free open source wiki and application platform for communities and enterprises. Deki Wiki is an easy to use and sophisticated wiki for authoring, aggregating, organizing, and sharing content. Deki Wiki is also a platform for creating collaborative applications, or adding wiki capabilities to existing applications.