edX has teamed up with CourseTalk to provide a platform for course reviews that includes star ratings and in-depth comments. The service, currently up and running on edX, displays a sidebar containing mini-reviews on each course description page. Users can then click through to read the complete reviews on CourseTalk.com to help them decide whether to take a course or not.
http://campustechnology.com/articles/2014/04/17/edx-taps-coursetalk-for-online-course-reviews.aspx