If you were to review my writing on MOOCs and similar phenomena you would see me most frequently refer to (what we would call) 'students' as 'participants'. The term 'participant' to me most accurately represents the relation between MOOC and an individual person - they are not 'students' because that implies studying and the master-student relationship, which are antithetical to MOOCs. Nor either are they referred to (much) as 'learners', as this suggests that learning is the dominant paradigm at work here. In fact, the logic of MOOCs is not the logic of learning, but rtaher, of participation, and that's why I use the word. (Not always, of course, because a needless 100% consistency here would confuse people). The Inside Higher Ed article looks at the same question, but with respect to Coursera, EDx, and the rest of the America MOOCs. In this regard, may I respectully suggest that the best and most appropriate word is 'customer'.