Wikipedia
Liferay Portal is a free and open source enterprise portal software product. Distributed under the GNU Lesser General Public License and optional commercial license, Liferay has been declared "Best Open Source Portal" by InfoWorld in 2007. It is primarily used to power corporate intranets and extranets.
Written in Java, Liferay Portal is a web platform with features commonly required for the development of websites and portals. Liferay includes a built-in web content management system allowing users to build websites and portals as an assembly of themes, pages, portlets/gadgets and a common navigation. 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.
Although Liferay offers a sophisticated programming interface for developers, no programming skills are required for basic website installation and administration.
Liferay Portal is Java-based and runs on any computing platform capable of running the Java Runtime Environment and an application server. Liferay is available bundled with a servlet container such as Apache Tomcat.