Drupal (www.drupal.org) is an award-winning web publishing software which allows to create different websites. With its extremely powerful content management system Drupal allows to easily publish, manage and organize a wide variety of content on the website.
 
Tens of thousands of people, small and large companies and organizations are using Drupal to power scores of different web sites. It is estimated that around 250,000 websites use Drupal worldwide! Some of the companies, governments, organizations using Drupal are: The White House, The Economist Magazine, The New York Observer, World Food Programme, UN End Poverty, Oxfam International, The Harvard Voice, Cambridge University Entrepreneurs, Sony BMG Myplay, MTV UK, Amnesty International, Greenpeace UK, Human Rights Watch, Fedex news, Nokia Research Centre, Yahoo Research, and more.
 
You may see some of the high-profile websites powered by Drupal in this video prepared by Agnian.

Drupal is distributed under an open-source license (GPL or "GNU General Public License") and is maintained and developed by a community of thousands of users and developers.
 
Drupal supports different kinds of social web systems enabling individuals, teams, and communities to create and maintain community web portals, corporate web sites, social networking sites, personal web sites or blogs, and much more. Drupal powers:

• 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

Unlike many other content management systems Drupal is designed to be a framework for quickly and reliably building all kinds of powerful web applications. That means that while Drupal can be used to power simple websites it is also an excellent framework to be used to develop very complex e-commerce or community websites.

Drupal Principles:

• Modular and extensible:  Drupal aims to provide a slim, powerful core that can be readily extended through custom modules.
• Quality coding:  High quality, elegant, documented code is a priority over roughed-in functionality.
• Standards-based:  Drupal supports established and emerging standards.  Specific target standards include XHTML and CSS.
• Low resource demands:  Drupal puts a premium on low-profile coding (for example, minimizing database queries).  Drupal should also have minimal, widely-available server-side software requirements.  Drupal should needs a platform with a web server, PHP, and either MySQL or Postgresql.
• Open source:  Drupal is based on the open source philosophy of collaborative free software development and is licensed under the GPL.
• Ease of use:  Drupal aims for a high standard of usability for developers, administrators, and users.
• Collaboration:  Drupal development supports open, collaborative information sharing systems and approaches.