By Stephen Downes - Stephen's Web. MOOCs: A Review of the State-of-the-Art
Ahmed Mohamed Fahmy Yousef, Mohamed Amine Chatti, Ulrik Schroeder, Marold Wosnitza, Harald Jakobs, CSEDU 2014 - 6th International Conference on Computer Supported Education, 2014/10/17

This is quite a good overview of the current state of MOOCs with a number of good images, statistics and definitions, making it a great reference paper for future discussions. More...