http://www.washingtonpost.com/blogs/answer-sheet/post/sal-khan-responds-to-critic/2012/07/25/gJQA83rW9W_blog.html
Following Karim Kai Ani's post in The Answer Sheet (http://www.washingtonpost.com/blogs/answer-sheet/post/khan-academy-the-hype-and-the-reality/2012/07/22/gJQAuw4J3W_blog.html), Sal Khan replies with a post of his own. As he's done before, he stresses how Khan Academy is not a cure-all and he appreciates feedback. Then he claims that "Karim's corrections are very incorrect" and links to a rebuttal video (http://www.youtube.com/watch?v=TNaQJjLAhkI) that responds to Karim's argument that he's been incorrect in the way he teaches slope.