[abecedarius]

This difference bothers me in the new online courses too: most of them use video lectures. Some of the problems don't carry over (the ones about the audience as a mass), but some do (sentences going by like a stream neither the speaker nor the listener can as easily go back and forth over). I feel we're losing something from when a book was the way to reach an audience, and we could add the interactivity and a lot of the other new advantages without losing the benefits of text.

Funny how that line about "The moving finger, having writ" has it backwards now with text easier to revise than speech. (This remark's an addition to my original comment.)