As an autodidact interested in exploring more mathematics, of course I learned about Khan Academy. One look and I was impressed, but that didn't last long. Though the videos are well done all around, there's no clear curriculum to follow. Or if there is a curriculum, it's not obvious. Instead, I have a bazillion videos to choose from. Which videos depend on knowledge in other videos, and which ones can be done in parallel? No idea.

Education's past is a series of textbooks (plus supplemental info and exercises), providing a clear path to learning. Khan Academy, such as it now stands, is a video analog of textbook chapters as discrete units all in an unorganized pile. Until more is done in the neglected areas, Khan Academy will remain an extremely valuable resource, but not a curriculum. Even if/when these missing bits are done this will only be the future of delivery of fairly traditional materials.

The real future of education is a computerized personal tutor that provides individual assessment, guidance, alternate explanations where comprehension lacks, encouragement to pursue natural ability and enthusiasm, etc. That's pretty ambitious, but not at all inconceivable. We're close enough to being able to achieve it that we should hold up this ideal goal so we know the right direction as we build the pieces.