Drupal is a open-source CMS written in PHP and used for personal blogs to corporate, political, and government sites across the world. It is also known as as a web application framework. It also used effectively for knowledge management and business collaboration. User profiles management, User Management, OpenID support, access statistics and logging, page layout customization, blogs, books, comments, forums, and polls; caching and feature throttling for better performance, system administration, RSS feeds, menu management, advanced search, RSS feed and feed aggregator, support to workflow tools (triggers and actions), localization built on top of gettext – the GNU internationalization and localization (i18n) library, auto update notifications for new versions of modules, themes, or the Drupal core etc. are some of the main features of Drupal. Drupal 7 requires PHP 5.2.5 or higher. Drupal supports web servers such as IIS, Lighttpd, Apache, Hiawatha, Cherokee or Nginx; and a database such as PostgreSQL, SQLite, MongoDB, MariaDB, MySQL, or Microsoft SQL Server.