OTOH, being able to hit rewind is invaluable. Or hitting rewind, googling a bit, and then continuing. My first online course was Andrew Ngs when he at Stanford,

OTOH, being able to hit rewind is invaluable. Or hitting rewind, googling a bit, and then continuing. My first online course was Andrew Ngs when he at Stanford, and being able to rewind and google whatever he just said was fantastic. It also meant I could play it at 1.5x speed for the bits I had no trouble with. If we wanted to make it better to support interactive questions, one could imagine an online system with videos plus "Push now for live help". Or facetime your peers.