IBM's 5th article on Drupal
In this series, the IBM® Internet Technology Group designs, develops, and deploys a closed community Web site using a suite of software that is freely available. If you followed the instructions in the previous articles, you now have a generic Drupal installation. You can begin to add content and modify the style. This article introduces the Drupal programming model used in developing Web sites and includes a description of different types of content, developing new features using modules, implementing hooks to enable those modules, and site URL design.
This article gives you an overview of the Drupal content management system. We'll describe the common building blocks and discuss some common assumptions of the Drupal approach. It is helpful to understand core concepts and basic Drupal terminology as you go through this article and beyond.