WordPress is publishing software with a focus on ease of use, speed and a great user experience. WordPress is blessed with an active community, which is the heart of open source software.

WordPress is a powerful personal publishing platform, and it comes with a great set of features designed to make your experience as a publisher on the Internet as easy, pleasant and appealing as possible. We are proud to offer you a freely distributed, standards-compliant, fast, light and free personal publishing platform, with sensible default settings and features, and an extremely customizable core.

http://www.wordpress.org