It is often said that in a MOOC every letter is negotiable. Much has been written about the many interpretations of open but maybe the most problematic is the final letter - C for course. Are MOOCs really courses? Many of the mainstream ones are definitely built like courses with a clear linear structure but the original connectivist model is more fluid. Whatever the intention of the MOOC-designers, the problem is whether the learners see the MOOC as a coherent course that must be followed from units 1 to 10 or whether they see it as content and discussions to dip into and investigate when their curiosity is awakened. Maybe the main reason for the notoriously low completion rates of MOOCs is the fact that most learners do not see them as courses to be followed from A to Z.
Stephen Downes hits the nail on the head in a new post about this issue, Like reading a newspaper. If we compare a regular course to a book which must be read from cover to cover then a MOOC is more like a newspaper that you read very selectively. A course, like a book, is meant to be followed from start to finish and abandoning it midway is seen as a failure to engage. Downes suggests that the connectivist MOOCs he's associated with offer learners a range of learning paths and a flexibility in approach that is unlike a regular course.
But our MOOCs are not designed like that. Though they have a beginning and an end and a range of topics in between, they're not designed to be consumed in a linear fashion the way a book is. Rather, they're much more like a magazine or a newspaper (or an atlas or a city map or a phone book). The idea is that there's probably more content than you want, and that you're supposed to pick and choose from the items, selecting those that are useful and relevant to your present purpose.
A newspaper is not a failure if noone reads it cover to cover just as a buffet is not a failure if we don't eat every dish. I suspect that even on the more linear and traditional xMOOCs of Coursera, edX and others, many learners treat them as newspapers/buffets rather than as a coherent course that must be followed. They dip in and investigate the parts that seem interesting and their disappearance should not be confused with dropping out of a formal university course. The completion rate comparison is comparing apples with pears basically.
Yet another argument for scrapping the term MOOC. How about Massively varying in size, open depending on your interpretation of the term, online (that one's OK), learning arena that may or may not resemble a course ...