I am still in the process of converting the MOOC to deliver from this site. Meanwhile, I've been looking at ways to import and export models (not model data) between Moodle sites and even non-Moodle systems. The two standards I am currently looking at are:
http://dmg.org/pmml/v4-3/GeneralStructure.html (a JSON standard)
http://dmg.org/pfa/index.html (an XML standard)
Are there other model representation standards any of you would like us to consider? Please comment here or in MDL-60944.