The enhanced version of Khan Academy includes time-syncing between devices--no Internet connection required--an interactive transcript of the lectures for easy searching, and a handy scrubber for moving between parts of the lectures.
this sort of online platform puts the pace and path of learning firmly in the hands of the student. Work at your own level, learn concepts in the order that makes the most sense to you. Learn when you want to learn, how you want to learn.
HOWEVER, none of this, for a moment, displaces the teacher. On the contrary, it amplifies teacher skills. It may also facilitate the ability for teachers to play to their strongest card:
We should not try to recreate what Salman Khan of the Khan Academy and others are doing so brilliantly, namely to meticulously build up entire curricula on video. No. TED is known for its ability to evoke curiosity, wonder, and mind-shifting insight. That should be our prime goal here. Short lessons that spark curiosity.