I'm pretty sure most universities have a company mission that appeals to both men and women and they haven't suddenly seen a 2:1 f/m ratio in CS majors. What makes Khan so different?

He might have a point in that a lot of women seem to aspire to be teachers. For example when I got my maths degree, 99% (estimated) of the women sitting in the lectures with me were studying to become teachers. Perhaps working for Khan Academy somehow seems close enough to teaching.

What % of the applicant pool was women?

Some hard numbers would help this discussion.