There are lots of ways to describe the differences between xMOOCs--the courses produced by edX, Coursera, and Udacity starting around 2011--versus the cMOOCs--the original courses dubbed MOOCs in 2008 and 2009 by a number of university professors, mostly in Canada.
One of the best ways to distinguish between them is by thinking about their "killer app," the special tool that distinguishes them from previous generations of technologies.
For xMOOCs, the killer app is the autograder. xMOOCs emerge from the tradition of courses built in learning management systems. For the most part, the platforms built by Coursera, edX, and Udacity are no different than the platforms built by Blackboard, Canvas, Moodle, Desire2Learn, It's Learning, Schoology, Edmodo, Google Course Builder, and on and on. edX deserves a special mention for having an open source platform, but in terms of most functionality, the new xMOOC providers are re-building elements that have been built before. The one important is exception the autograder. What distinguishes xMOOCs from other LMS is that they can assign a grade (either computationally or through peer assessment) to a wide variety of response types--a technology that most LMS did not develop since they assumed that teachers would be doing that work for the managable numbers of people taking each course. These autograders allow xMOOCs to not just distribute lectures at scale (like iTunes University) but to certify student competencies at scale.
So, xMOOC = LMS + Autograder.
If xMOOCs are a branch of the LMS tree, cMOOCs are a branch of the social Web. If xMOOCs whisk people away from the open Web into a walled garden, cMOOCs are built upon the assumption that people should do their learning work for a course in the same spaces that they do their other online activities. cMOOCs encourage people to produce and consume ideas in the networks that they already use: on Wordpress blogs, Twitter accounts, Flickr and Instagram photostreams and so forth. The signature challenge, then, is how best to corral all of this activity into a coherent, searchable body of work that can constitute the basis of a course. The solution to this challenge--the killer app for cMOOCs--is the syndication engine. Stephen Downes's gRSShopper was used for this purpose for some of the earliest MOOCs, and FeedWordpress was used for the recent ETMOOC.
In these cMOOCs, faculty distributed course content through a central website, and participants created responses and performances of understanding across the open web, using a series of hashtags that are recognized by the syndication engines. The syndication engines grabbed all of this content into a central hub, so it can be found, parsed, curated, and connected. You can view one example of this syndication in the recent Connected Learning MOOC (#clmooc) from the National Writing Project either by visiting their blog hub or twitter feed.
So, cMOOC = Web + Syndication Engine.
As I've started to get to know the various HarvardX stakeholders, I've had a number of faculty, fellows, and others talk to me about how they'd like more social features in their courses, features which are currently impossible in a walled garden like edX: extending conversations out to friends and family, facilitating in-person meetings, connecting multiple cohorts of a course over years. I've started joking with folks, "Humans have built a system for online social learning: it's called the World Wide Web." I won't be surprised if in the months ahead, more HarvardX courses put more resources into developing social learning environments that borrow from the insights that the cMOOC pioneers have developed.
I did some playing this summer with syndication engines myself. With help from the extraordinary Alan Levine of ds106 fame, some colleagues and I built a new online learning environment for the Future of Learning Institute held by Project Zero and the Harvard Graduate School of Education. You can see our syndication engine hoovering up content from blogs, Twitter, Instagram, and even email posts at futureoflearningpz.org/flow.
Check out the Future of Learning Twitter stream at #HGSEPZFOL.