Drupal

Drupal is a free software package that allows an individual, a community of users, or an enterprise to easily publish, manage and organize a wide variety of content on a website. Hundreds of thousands of people and organizations are using Drupal to power an endless variety of web sites, including  * Community web portals  * Discussion sites  * Corporate web sites  * Intranet applications  * Personal web sites or blogs  * Aficionado sites  * E-commerce applications  * Resource directories  * Social Networking sites