I teach science classes at the college level, and I find these Internet courses extremely promising. Not only do they offer help to people who might not get it otherwise, they also put pressure on faculty who waste lecture time, teach for themselves and not for the students, and insist on rote memorization and mass-graded tests of regurgitation. In light of these new resources, the only way that colleges and universities can justify enormous tuition costs is by providing fast and thoughtful expert feedback, a supportive environment filled with motivated peers, solid lab instruction, available research and job opportunities, and honest, trustworthy grading that can't be bought or compromised.
Now, I've heard that formal education "can't be replaced" with the canned summaries of Salman Khan and his like, and that's true to a point. But these criticisms ignore something important: Khan teaches with joy, making his points clearly and concisely. Does this give students all the depth they need? No, but neither does a time-wasting lecture by a tenured prof who just wants to get back to the lab and be done with it. Let's reward universities that serve the public by putting classes online and training their faculty to teach in an engaging way.
Some teachers consider these methods impersonal. There's truth in that. And I'd bet that centuries ago, scribes felt threatened by the printing press, and thought that mass-produced books were impersonal. But as personal and gorgeous as illuminated manuscripts could be, cheaper books and widespread literacy are the greatest developments civilization has ever produced, right up there with antibiotics.