The attrition rate is due to the lack of cost involved in opting out if you find yourself unable to keep up with the course / too many courses. Being able to tr

The attrition rate is due to the lack of cost involved in opting out if you find yourself unable to keep up with the course / too many courses. Being able to try and see if you can do a course (despite the other commitments in your life) is actually very attractive because most people cannot assess their goals or time budget that accurately. From the MOOCs' point of view, this is a worthwhile feature because while it does increase the false positive rate tremendously, it also increases the true positive rate : more people sign up for the course because the barrier to entry is low and end up completing it. Also, it does a wonderful job of introducing a new product to the market : I do not know a single friend in my circle who has not tried out Coursera. And guess what, I would happily pay up if they charge a reasonable fees in the future!