OP here, actually floored by the rapidity and variety of responses. Thanks HN.

I'll take this opportunity to float an idea that's been kicking around in my head for a long time.

The premise is to:

1) (this is almost certainly the easy part) build out a platform that is like a two-way khan academy - teacher and student, with at least the teacher having a tablet and a stylus that function well, sharing a digital blackboard, with a video chat optional -- where a student of something in a relatively privileged situation teaches a student of the same thing in a relatively less privileged situation -- where the sessions are stored and rewindable, both video and blackboard input.

2) the hard part; selling it as something to invest in and driving it to a point of having an endowment behind it, like Harvard's endowment, that allows the service to pay for moderation of student-teachers something like $12.00 USD an hour to teach, while subsidizing well-chosen students to have to pay something like $2 an hour to learn

it's been an idea for a passion project for a while