Palo Alto, Calif.

Andrew Ng is an associate professor of computer science at Stanford, and he has a rather charming way of explaining how the new interactive online education company that he cofounded, Coursera, hopes to revolutionize higher education by allowing students from all over the world to not only hear his lectures, but to do homework assignments, be graded, receive a certificate for completing the course and use that to get a better job or gain admission to a better school.

“I normally teach 400 students,” Ng explained, but last semester he taught 100,000 in an online course on machine learning. “To reach that many students before,” he said, “I would have had to teach my normal Stanford class for 250 years.”

Welcome to the college education revolution. Big breakthroughs happen when what is suddenly possible meets what is desperately necessary. The costs of getting a college degree have been rising faster than those of health care, so the need to provide low-cost, quality higher education is more acute than ever. At the same time, in a knowledge economy, getting a higher-education degree is more vital than ever. And thanks to the spread of high-speed wireless technology, high-speed Internet, smartphones, Facebook, the cloud and tablet computers, the world has gone from connected to hyperconnected in just seven years. Finally, a generation that has grown up on these technologies is increasingly comfortable learning and interacting with professors through online platforms.

The combination of all these factors gave birth to Coursera.org, which launched on April 18, with the backing of Silicon Valley venture funds, as my colleague John Markoff first reported.