When you learn for the sake of learning, rather than certification, there's little point in crossing all the t's and dotting all the i's, in entirely finishing a course. You take what you need from it, and move on. Lifelong learning precisely means that you mix education in more closely with the application of the information you have learnt. When I use these resources, I jump around from course to course because I am actively engaged in my education, trying to get exactly what I need to move on to the next step.

If MOOCs want people to follow the material point to point, from start to end, they will need to provide a level of certification which gives people a meaningful incentive to do so.