Drupal is content management software. It's used to make many of the websites and applications you use every day. Drupal has great standard features, like easy content authoring, reliable performance, and excellent security. But what sets it apart is its flexibility; modularity is one of its core principles. Its tools help you build the versatile, structured content that dynamic web experiences need. It's also a great choice for creating integrated digital frameworks. You can extend it with any one, or many, of thousands of add-ons. Modules expand Drupal's functionality. Themes let you customize your content's presentation. Distributions are packaged Drupal bundles you can use as starter-kits. Mix and match these components to enhance Drupal's core abilities. Or, integrate Drupal with external services and other applications in your infrastructure. No other content management software is this powerful and scalable. The Drupal project is open source software. Anyone can download, use, work on, and share it with others. It's built on principles like collaboration, globalism, and innovation. It's distributed under the terms of the GNU General Public License (GPL). There are no licensing fees, ever. Drupal will always be free.

-Model-View-Controller (MVC) design pattern. -Database Access Objects (DAO), Query Builder, Active Record, DB Migration. -AJAX-enabled widgets. -Authentication and authorization. -Yii is equipped with many security measures to help prevent your Web applications from attacks such as SQL injection, cross-site scripting (XSS), cross-site request forgery (CSRF), and cookie tampering. -Yii supports data caching, page caching, fragment caching and dynamic content.