As a classroom teacher I can say that Khan Academy is one of the best resources out there. We love it. Our students who don't understand a concept or need a little extra intervention have easy access to a short video clip in whatever concept they need. Thank you Khan Academy!

One of the best resources out there?  
What is good math pedagogy? The Khan Academy has *none* of it. It teaches procedures, not concepts. His average lesson, for example: all lecture and chalk (no interaction, nothing visual or concrete). He says I might use the word average non-mathematically, saying “the average voter wants…” or “the average student would like to leave early.” Of course, he really should have said “typical,” not average… that meaning has nothing to do with the concept of “average.” (Do “C” students want to leave early? And the “A” and “F” students don’t?) The closest he comes to mentioning what averages mean is to say that they "sort of represent" a group of numbers. He also refers to a multiplication problem as a sum, and expects students being introduced to averages to do algebra with variables on the bottom of a fraction. 
Okay, I thought, maybe I picked a lemon. I asked people if there were better ones. "The Beauty of Algebra" -- okay, he isn't talking about a procedure... well, except figuring out percents, and he says that to do that I multiply the percent by the number. Oh, really? I don't have to change it to a decimal?  
All the rest of the videos I saw were quick summaries of procedures... and I stopped watching them in disgust when he informed me that 2 x 1 was "two plus itself times one."  
The last time I checked, two plus two was four. 
I think it is an extremely sad commentary that people are lauding it. I don't know about your students, but *mine* deserve better than the fastest slapped-together videos stuck out there.