Moodle is an open-source learning management system (LMS) that is used by educators around the world. It has over 150,000 registered users on its main site and is used by universities like UCLA, UC San Diego, and Smith College. Moodle was designed to help foster online learning communities following social constructivist pedagogy. It has a variety of features that allow for online collaboration, including forums, wikis, quizzes, assignments and more. Moodle provides these features freely as open source software and has an active development and support community.