ATutor is a Web-based learning content management system (LCMS) designed for accessibility and adaptability by the Adaptive Technology Resource Centre at the University of Toronto. ATutor claims to be modular for new looks and functionality.
Like Moodle, ATutor is a PHP application with some 25,000 registered installations. With ATutor instructors and students can manage the courses they teach or are enrolled in, send messages to other participants, create workgroups and collaborate on courses, blog, share and track content, and store files among other things. (source: http://www.techworld.com.au/article/223565/10_open_source_e-learning_pro... )