MOOCs (Massive Open Online Courses) are massive!!!
I did my first one 7 years ago (on Cousera; Martin Odersky’s course on Functional Programming with Scala).
Since then there has been an explosion of sites and offerings. By now it is clear that, if you do not know, how to use these sites to your own advantage you are putting yourself at a competitive disadvantage (from a skills development point of view).
Good experience. Recommended.