Drupal is a tool for building a wide variety of web portals. He appears, however, and as a content management system (CMS) and a modular web framework.
Drupal has become popular among developers, convenient both for beginners and for those companies that have long experience and offer a full service package.
The modular architecture of the core Drupal provides flexibility and provides almost unlimited possibilities to customize settings. In particular, very easy and convenient is to content management of a publishing system.