Well, not so much fallen, it's more that the acronym and the specific concept of "massively online" have faded, while online ed has continued to evolve. Companies like Coursera got their start during the MOOC craze a couple of years ago, but my impression now is that they have smaller courses, more asynchronous (at the individual's pace, rather than grouping students into huge cohorts just for numerical bragging rights), and of course, huge catalogs now.

I did a MOOC at the height of the craze. It was supposed to be about the newly-released DSM5 manual used by psychologists and psychiatrists. Part of it was traditional teaching material about the new manual and its standards, but you know me, I made sure that a lot of it was about encouraging discussion. Made sense, because it was very controversial at the time, had been for years leading up to the release. As it turned out, though, the buzz died off remarkably fast after the official release of DSM5, and so did traffic to the MOOC. They told me to build infrastructure capable of handling 100,000 students at a time in the course, and I did. We barely met 1% of the forecast.

I'm not doing another MOOC, thanks. But I still think there's a lot of value in online learning, and in my work these days, I focus on making it less isolating and alienating, again adding discussion features and study groups etc. wherever it makes sense, developing a concept of "social learning". We learn interacting with others from infancy, and I do believe that learning in total isolation is not our most optimal mode. (So I'm a hermit, sue me for hypocrisy. If you can find me.)