The problem with Coursera, IMO, is that despite the promise of free education for all, the very large amount of courses with a broad spectrum of usefulness and difficulty makes it too difficult to navigate and can cost a student hours of wasted time watching videos that may be far beneath or above the student's abilities. I would suggest Coursera creates a pre-exam section for all the courses so the student can have a slightly better understanding of what they are signing up for. Hell, they are promoting themselves as a Machine Learning repository, can't they do a basic suggest-a-course section based on pre-exams?
With that said, I love the idea of Coursera, Udacity, EdX, etc. and what they promote. I am one of those people who, despite being American, had zero chance of ever getting into college due to the quality of my inner-city high school and financial circumstances. Of course, the issue is that if you do grow up in this circumstance, you probably won't be able to take advantage of the free education because you may not have a computer. Regardless, anyone who wishes to partake can join with little more investment than a $200 computer from Walmart, so the financial excuse isn't quite the barrier that it once was.
How much opportunity do any of these courses open up? How much do employers give a hoot about a silly certificate from a pseudo-school that rides on the backs of watered-down Ivy League classes? Employers still take a degree from DeVry more seriously than the scattered layout of MOOC, and until this is changed, there will never be tangible proof or progress in the sphere.
I could tell employers all day that I read, and worked through, SICP and Cormen, but why should they care? They shouldn't because there was no one around to tell me my code is wrong. I can show employers websites I built using exotic languages such as Clojure, but why should they care when I can't pass a basic whiteboard test? I could tell them that I can proficiently write in x y z language, but they don't care and they shouldn't. To all of those people who suggest that employers don't care about your background education and only care about the projects you worked on, I challenge you to point out how many of your coworkers don't have at least something that resembles a Formal Education (TM). Coursera is not a Formal Education (TM). The proof will come if, and only if, one day a student self-learned from Coursera with a large portfolio with self-projects nails a job over a kid from MIT with no portfolio. No one, at this point, can seriously say this is happening and a convincing scale.