Plone is a user-friendly powerful content management system - ideal as an intranet and extranet server, as a document publishing system, a portal server and as a groupware tool for collaboration between separately located entities

Features:

• Plone is powerful and flexible. It is ideal as an intranet and extranet server, as a document publishing system, a portal server and as a groupware tool for collaboration between separately located entities.
• 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 40 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.