The University of Pennsylvania has surveyed ca. 35,000 students who participated in one of their MOOCs (“at least one full lecture”). An infographic of the findings are available in the summary in New Republic.
Comparing the percentrage of those in the general populus who have college degrees with those who have participated in a University of Pennsylvania MOOC, the survey revealed that across all country types (e.g. US, Developed, Developing and BRIC) a greater proportion of MOOC participants have college degrees than in the general population. For those in the US, 86% of MOOC participants have college-level degrees compared to 32% of the population, while for developing countries 79% of those taking the MOOC have college-level degrees compared to 6% of the population.
This data was also reported in http://www.scidev.net/global/education/news/survey-suggests-moocs-are-failing-to-educate-the-poor.html