The first really large enrollment Massive Open Online Course (MOOC) was run by Stanford University in 2011. During the subsequent four years, the success of these courses as measured by completion rate has been very low. However, the courses have continued to be improved and enrollment in these courses has grown remarkably. Quoting from an article written by Dhawal Shah (12/28/2015):
Student enrollments in MOOCs doubled this year. In fact, more people signed up for MOOCs in 2015 than they did in the first three years of the “modern” MOOC movement (which started in late 2011—when the first Stanford MOOCs took off). According to data collected by Class Central, the total number of students who signed up for at least one course has crossed 35 million—up from an estimated 17 million last year.