What is Liferay?
Liferay is an open source and free enterprise portal, which is mainly used to enable corporate extranet and intranet. It is also described as a web application framework or content management framework. It has all the features that a website can offer to its users.
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.
The reasons to use Liferay Portal for your website are simple: it provides a robust platform to serve your site to all clients, be they desktop, mobile, or anything in between; it provides all the standard applications you need to run on your site; and it provides an easy to use development framework for new applications or customization.
In addition to this, Liferay Portal is developed using an open source methodology, by people from around the world. The code base is solid, and has been proved to be reliable and stable in mission critical deployments in diverse industries.
Video for Liferay Introduction
https://www.youtube.com/watch?v=yKP3oArE8lk