There is actually a very active social aspect to these Coursera and Udacity etc courses. You clearly haven't signed up yet, check out the forums for each class

There is actually a very active social aspect to these Coursera and Udacity etc courses. You clearly haven't signed up yet, check out the forums for each class that are very active, the subreddits (main hub is at /r/OnlineEducation), and the many IRC channels (main hub is #free-class on Freenode). These act as effective study groups with people helping and discussing with each other many things about the courses at hand and related things. And as the other commenter noted, the students' backgrounds very greatly which makes it all the more interesting.