Very interesting perspective. I like this bit on lectures and attention spans:
Online education can also break the artificial lecture length of 50–90 minutes. Many teaching experts say that adult attention span is 10–15 minutes in a lecture, with many suggesting that attention span has declined in the Internet era. A good professor can refocus the attention of motivated students over longer periods. Nevertheless, it is clear that the standard lecture length has not been determined by optimal learning time but by the high fixed costs of traveling to school. Lower the fixed costs and lectures will evolve to a more natural level, probably between 5–20 minutes of length—perhaps not coincidentally the natural length of a lecture is probably not that different from the length of a typical popular music track or television segment.