TALK OF THE TOWN: A-listers Bill Gates, Sal Khan, and Bror Saxberg gathered at Microsoft's 16th annual CEO Summit last month to talk digital textbooks, flipping the classroom, data, and biz models. And for those itching for more videos, be sure to check out this high-energy discussion between Khan and Stanford president John Hennessy on the rising price of higher education and credentialing. Moderator Walt Mossberg begins: "Is it either moral or sustainable for elite colleges and universities to be charging what is approaching $60,000 a year to go to college?"