Created by two computer scientists at Stanford University, Coursera is an interactive online learning system that offers free massively open online courses, or MOOCs. Courses are available in a wide range of topics, including the humanities, medicine, biology, social sciences, business, computer science and others. The platform breaks lectures into segments as short as 10 minutes and offers quick online quizzes as part of each segment.
Universities that have partnered on the project and are offering courses on the site include the University of Michigan, the University of Pennsylvania and Princeton University, among others. See a full list of schools and courses here.
You can check out a list of the most popular courses on Coursera here, and you can read a Q&A on MOOCs with a professor who taught one on Coursera here.