Drupal is an open-source content management system written in the programming language PHP. Drupal is a free software package that allows an individual or a community of users to easily publish, manage and organize a wide variety of content on a website. We use Dupal to power scores of different web sites, including

Here are some typical Drupal usages:

• Content management - Members can publish stories, images, blogs, polls, forums, etc. via a simple, browser-based interface. Administrators can easily customize the design of their Drupal installation.
• The flexible classification system allows hierarchical classifications, cross-indexing of posts and multiple category sets for most content types. Access to content is controlled through administrator-defined user permission roles. A search option is also available.
• Weblog - A single installation can be configured as an individual personal weblog site or various individual weblogs. Drupal supports the Blogger API, provides RSS feeds for each individual blog and can be set to ping weblog directories when new content is posted on the home page.
• Discussion-based community - You can use successfully a Drupal site as a discussion forum. It is simple for members to discuss new posts in its comment boards that are attached to most content types. Administrators can control whether content and comments are posted without approval, with administrator approval or through community moderation. Communities can subscribe to and then discuss content from other sites with the built-in news aggregator.
• Collaboration - As used for managing the construction of Drupal, the project module is suitable for supporting other open source software projects. The wiki-like collaborative book module includes versions control, making it simple for a group to create, revise and maintain documentation or any other type of text.
• FAQ - The Drupal installation can be used as a frequently asked questions platform. You can have a look at the Full Drupal Feature Overview for a better comprehensiveness.

Drupal with Model View Controller:

Many users & community - so it is easy to find solutions to your problems. The large community guarantees that Drupal will have a further progress.

Conclusion: A large number of man-hours have clearly gone into Drupal. It's a highly detailed system, boasting a range of features not found in rival products. That said, to set it up isn't as straight forward as it could be, and it cannot be run straight "out of the box."
What Drupal does provide is an extensible framework, especially beneficial for use on larger intranets, which will allow you to expand and improve your intranet over time. The screens for adding new articles are simple, and the administrator of the system is given the ability to veto content submitted by contributing authors. If you have the time and expertise, it's well worth getting to grips with the nitty-gritty of Drupal if you'd like to fully customize it's operation.
Drupal is a powerful system, but not alone. Its rivals are numerous.