Sure, there's differences with the MOOC community. The biggest three in my opinion are that
1) The courses are free with no obligation. Because of this, people can and will sign up for trivial things like looking at part of a single lecture.
2) The environment is different. Because the dedicated school environment is replaced with the same environment where most people play their computer games, and there is no one to crack the whip, and there is no dedicated timeslot in people's schedules, people who intended to take a full course may have trouble motivating themselves to complete it.
3) The completion certificate is worthless. No one gives a crap if you completed a MOOC course or not, and if they did it would be too easy to fake/cheat. And the person taking the course has a pretty good idea of what they know, so to them it's just a pat on the back. Besides this being mildly discouraging in general, it means there is very little reason to do the often boring assignments that would be required to complete the course.
Basically, all the worst problems of a MOOC could be fixed by having a "school" where you went in on a schedule and had someone watching over you. This would provide the motivation and environment some people need to succeed, and because it wouldn't be free it would weed out the people who didn't intend to carry through and provide the motivation of a sunk cost to continue. It would also help the certificate to be worth something, because there is someone to verify that you didn't cheat and that it was, in fact, you who took the class. At this point you're probably ready to complain that doing it this way exactly eliminates every advantage a MOOC was supposed to have. However, this sort of thing would be cheaper than a regular school and would also help legitimize MOOC even for people who do it on their own.