"MOOCs – massive open online courses – are loosely modeled on traditional college courses. The immediate differences are clear in the name – massive (high enrollment, dispersed geographically), open (articulated to free and accessible), and online (web-based facilitation, although for many online also signifies non-human and non-residential). MOOCs are mostly non-credit granting and mostly free. Weekly video lectures anchor courses, around which crowd-sourced homework and Blackboard-like forums orbit. Social media serves as digital TA. Most MOOCs are taught by faculty or instructors at traditional four-year universities worldwide. Three organizations – Coursera, Udacity, and edX – currently dominate the field."