Moodle: Modular Object-Oriented Dynamic Learning Environment is a free and open-source e-learning software platform, also known as a Course Management System, Learning Management System, or Virtual Learning Environment. It has a significant user base with 52,153 registered sites with 30,176,528 users in 2,770,832 courses (as of March, 2009).
Moodle is designed to help educators create online courses with opportunities for rich interaction. Its open source license and modular design mean that people can develop additional functionality. Development is undertaken by a globally diffused network of commercial and non-commercial users, streamlined by the Moodle company based in Perth, Western Australia