I'm fascinated by Coursera and other MOOCs (Massive Open Online Courses). It's both surprising and not at the same time that less than 10% of enrollees (if I recall correctly from the book College (Un)bound) in these classes ever wind up finishing. Unsurprising if you take the signalling theory seriously, because these MOOCs don't hold a candle to a traditional four-year degree where you pay lots of money and get a sheepskin, so there's less payoff in the end. But the high dropoff rate is surprising because I figure that a sizeable chunk of people who enroll in these classes (a) know that it's not really going to further their career but is merely for education's, and so (b) take classes that they're genuinely interested in. People therefore must be dropping these classes because they underestimate the time commitment or they overestimate their interest in a subject. Both completely understandable, but lamentable. Thanks for being a part of the 10%.