Online education has been around for decades,with many universities offering online courses to a small, limited audience.What changed in 2011 was scale and availability, when Stanford University offered three courses free to the public, each garnering signups of about 100,000 learners or more.The launch of these three courses, taught by Andrew Ng, Peter Norvig, Sebastian Thrun and Jennifer Widom, arguably marked the start of the modern, instructor-‐directed MOOC (sometimes“xMOOC”). Each of these MOOCs offered learners the opportunity to watch online lectures, do machine-‐graded homework, and earn a “Statement of Accomplishment” if they passed the class.