Drupal is a popular open-source content management system (CMS) and web application framework used for building and managing websites and web applications. It is written in PHP and supported by a vast community of developers and contributors worldwide. Drupal allows users to create, organize, and publish content easily and efficiently.

Key features of Drupal include:

1. Content Management: Drupal provides a flexible and robust content management system, enabling users to create, edit, and organize content with ease. It supports various content types, including articles, pages, blogs, forums, polls, and more.

2. Customizable and Extensible: Drupal's modular architecture allows users to extend its functionality by installing additional modules contributed by the community. These modules can add various features, such as user authentication, SEO tools, e-commerce capabilities, and more.

3. Themes and Layouts: Drupal offers a theming system that allows users to customize the look and feel of their websites easily. There are numerous pre-designed themes available, or users can create their own to match their branding and design requirements.

4. User Management: Drupal has robust user management features that allow administrators to create and manage user accounts with different roles and permissions. This feature is particularly useful for websites with multiple contributors or community-driven content.

5. Scalability: Drupal is known for its ability to handle websites of all sizes, from small personal blogs to large enterprise-level applications. It can efficiently manage high-traffic websites and applications with appropriate server configuration.

6. Security: Security is a top priority for Drupal, and the community actively works to identify and patch vulnerabilities. Regular updates and security releases are made available to keep Drupal installations secure.

7. Multilingual Support: Drupal provides built-in support for multilingual websites, allowing users to create content in multiple languages and cater to a diverse audience.

8. Community Support: With a large and active community of developers, designers, and users, Drupal benefits from ongoing support, regular updates, and a wealth of online resources.

Drupal is widely used by organizations, businesses, governments, and individuals worldwide to build a wide range of websites, including corporate websites, government portals, e-commerce platforms, community forums, and more. Its flexibility and extensive range of features make it a popular choice for various web development projects.