I rather see academic books for free on the web, I am not much of a video guy, no time even for a one minute youtuber. Kudos to the Khan Academy for their effort, but more is needed in the free ebooks arena.
Khan's fairly good at explaining stuff, but I have to view all of his material at double speed -- otherwise the repetitions and "uhm"s would be too bothersome. Same content could be delivered in half the time if written and read.
Transcribing the narration and converting the "chalkboard" to text/svg/flash/whathaveyou would be a huge win.