Liferay Portal is a free and open source enterprise portal written in Java and distributed. It is primarily used to power corporate intranets and extranets.
Liferay Portal allows users to set up features common to websites. It is fundamentally constructed of functional units called portlets. Liferay is sometimes described as a content management framework or a web application framework. Liferay's support for plugins extends into multiple programming languages, including support for PHP and Ruby portlets. Liferay Portal is Java based and runs on any computing platform capable of running the Java Runtime Environment and an application server.

Features

• Out-of-the-box Tools
• SOA Framework
• Secure Single Sign On (SSO)
• Granular, Role-Based Authorizations
• Communities & Organizations
• Single-Click Configuration
• Dynamic Drag & Drop
• Work From Your Desktop
• Search & Tagging
• Personal User Pages
• Multi-language Support

Official WebSite http://www.liferay.com/
SourceForge http://sourceforge.net/projects/lportal/