Salman Khan's recent TED Talk is now available online. I urge you to watch it.

I imagine that if you're a reader of this blog, you're already familiar with Khan Academy and its vast library of online educational videos. Perhaps you've watched some of them and sat through a lesson or two on algebra, differential equations, or compound interest.

Regardless, watch the TED Talk.

While it was Sal's YouTube videos that won him the initial attention and praise from the press (and from powerful donors like Bill Gates and Google), Khan Academy is creating more than videos these days. The organization has worked to develop an adaptive learning platform around its educational content. This includes exercises that accompany the materials and assessments that gauge whether or not students are ready to move on to the next concept. (Me, I'm not in a huge rush to quantify things like Sal Khan is. I prefer narrative to numbers. But I'm a former folklorist. He was a hedge fund manager. So there you go.)

I have heard some grumblings about Khan Academy lately, concern that this sort of video catalog aims to somehow replace teachers in classrooms, concern that praise of Khan as the "future of education" comes at the expense of trained educators and "teaching professionals." In our current anti-teacher climate, these sorts of fears don't seem entirely unwarranted, quite honestly. After all, we see Sal Khan onstage with Bill Gates, someone who readily calls for larger class sizes (i.e. fewer teachers) and for the end to bonuses for teachers who pursue graduate degrees.

Khan says his video lectures are assigned as homework, giving classroom teachers more time for individualized attention and instruction. In the talk, you'll hear him speak about the pilot program with Khan Academy and the Los Altos School District, and you'll hear something that I look for in all education technology endeavors: "We have a very tight design loop with the teachers" and "It's all been teacher driven."

Teacher-driven. That's important. But we need more teachers not just to give input on what Khan Academy should look like. We need teachers to try their hands at recording video lectures, to experiment with flipping their classroom. (I know Karl Fisch is trying this with his algebra classes, and I'd like to hear about others.) While Sal's teaching style might work for some students and for subjects, he isn't going to teach everyone everywhere.

When I had a chance to interview Sal Khan last year, he said something that's stuck with me since: "teachers don't scale." While web technology does allow his video content to be delivered at a massive scale, that's a technical solution; it doesn't address the human element. And while I remain a huge fan of Khan Academy, we need more Sal Khans. In other words, we need more good teachers. And we need those teachers videotaped with their materials available online. Teachers do need to scale.

Oh, and we need more standing ovations for all teachers.