Moodle is an open source learning management system (LMS) written in PHP.
Moodle is an Open Source Course Management System (CMS), also known as a Learning Management System (LMS) or a Virtual Learning Environment (VLE). It has become very popular among educators around the world as a tool for creating online dynamic web sites for their students. To work, it needs to be installed on a web server somewhere, either on one of your own computers or one at a web hosting company.
Originally developed by Martin Dougiamas in Australia, it is used world-wide by many places of learning.
According to Moodle.org's stats, as of February 2013, there are over 77,000 registered sites using Moodle in over 225 countries, serving over 7 million courses with over 66 million users.