David Kaplan on Sal Khan

In an undistinguished ranch house off the main freeway of Silicon Valley, in a converted walk-in closet filled with a few hundred dollars' worth of video equipment and bookshelves and his toddler's red Elmo underfoot, is the epicenter of the educational earthquake that has captivated Gates and others. It is here that Salman Khan produces online lessons on math, science, and a range of other subjects that have made him a web sensation.

Khan Academy, with Khan as the only teacher, appears on YouTube and elsewhere and is by any measure the most popular educational site on the web. Khan's playlist of 1,630 tutorials (at last count) are now seen an average of 70,000 times a day -- nearly double the student body at Harvard and Stanford combined. Since he began his tutorials in late 2006, Khan Academy has received 18 million page views worldwide, including from the Gates progeny. Most page views come from the U.S., followed by Canada, England, Australia, and India. In any given month, Khan says, he's reached about 200,000 students. "There's no reason it shouldn't be 20 million."

Sal Khan: Bill Gates' favorite teacher by David Kaplan

David Kaplan is one of the best writers on the Irvington Parents Forum. Probably the best, as a matter of fact, and that's saying something, because there are a lot of good writers on the Forum.