Drupal is an open-source content management framework and content management system built with PHP and MySQL. It supports content authoring, management, and publication. Drupal allows users to build websites with modular add-ons and extensions that provide dynamic features like forums, polls, media galleries, blogs, and e-commerce. Drupal 7 introduced new features like entities, fields, and bundles, while Drupal 8 is built on Symfony and uses Twig templating and Guzzle for web services to improve performance and support mobile and multilingual capabilities.