Drupal is a free "as in beer" open source Content Management System (CMS) that has emerged as the most powerful and flexible CMS out there. Drupal has become the CMS of choice for the serious web developer because of it's elegant and logical code base and api and its easy customizability. People often ask what can you build with Drupal - the answer is, anything you want.

One advantage to using a community supported project like Drupal are the hundreds of contributed modules that provide all kinds of functionality. Chances are good that a module already exists for that key feature and although it may not meet 100% of your requirement out of the box, it most likely will provide an excellent basis for helping us to deliver a solution to you much more quickly. Drupal is right at home serving up a simple brochure type site as it is scaling up to a huge traffic sites such as TheOnion.com.

One metric by which you can gauge Drupal's popularity is to monitor all of the major websites launching and/or converting over to Drupal on a weekly basis. Tens of thousands of websites now run on Drupal.

Recently a new company called Acquia was created by the founder of Drupal to put some commercial clout behind Drupal. Acquia is to Drupal much like Red Hat is to Linux. You can learn more about Acquia here: Acquia.com.

You can learn even more about Drupal here: Drupal.org.