Is it really a problem that completion rates are low though? I'd argue that most people's time is better spent on things other than taking online courses.
I'm a proponent of making education accessible, but it seems that it is fairly easy to find good resources to learn just about anything online, particularly if it is related to computing. The real problem I think is motivation. Most college students don't try that hard in school, so I wouldn't expect most people taking online courses (particularly free ones) to try that hard either.
If you're motivated enough to learn the resources are already available to you. If not, I think the efforts of others to make you learn will have marginal effects at best.
Edit: I was replying to the first point about completion rates being low. I actually think the discussion idea is a good one and would be helpful for those who actually want to learn the material.
I think you're right that low completion rates aren't a problem. I don't have specific numbers, but I'd presume that most students who fail to complete an online course aren't motivated going in and are merely sampling or browsing. They'd probably drop out regardless and skew the completion rate horridly.
For everyone else, I'd imagine the motivation level is higher because of voluntary enrollment than a college student's who is forced to take certain classes.
Also, the current iteration of online education can survive on unassisted self-motivation. I can't recall the specific stat, but I believe 80%+ of students taking coursera classes already have a bachelor's degree. Most classes tend to be technical, where online resources are free and plenty. And given the self-paced nature of online classes, most students who learn best in group environments are probably pre-filtered and never sign up.
Perhaps discussions would be even more relevant as online education becomes more mass-adopted? Group tutoring for home-schooled kids, KUMON classes taught online, K-12 education where students need more hand holding, liberal arts classes where answers are subjective and can't be auto-graded, etc.
I'm a proponent of making education accessible, but it seems that it is fairly easy to find good resources to learn just about anything online, particularly if it is related to computing. The real problem I think is motivation. Most college students don't try that hard in school, so I wouldn't expect most people taking online courses (particularly free ones) to try that hard either.
If you're motivated enough to learn the resources are already available to you. If not, I think the efforts of others to make you learn will have marginal effects at best.
Edit: I was replying to the first point about completion rates being low. I actually think the discussion idea is a good one and would be helpful for those who actually want to learn the material.