Now Ng and Daphne Koller, a Stanford colleague, are launching a company called Coursera to bring more classes from elite universities to students around the world for free online.
"By providing what is a truly high-quality educational experience to so many students for free, I think we can really change many, many people's lives," Koller says.
Princeton, the University of Pennsylvania and the University of Michigan will join Stanford. Two Venture capitalists are investing more than $15 million in the company.
Koller says she believes online classes could bring university classes to millions of people who are now effectively cut off.
But to do this, these classes have to be effective at teaching more than just computer science. How will they teach hundreds of thousands of students to write?
"You've asked the right question," asks Al Filreis, a poetry professor at the University of Pennsylvania, "which is: You are really going to try to do a poetry course?"
They are. In fact, Filreis is the guy they have roped into doing just that. He will teach modern and contemporary American poetry online for free starting in the fall. He says he knows he's not going to be able to grade thousands of essays.
But "I am really, really game and open to other ways of understanding whether people are getting it because my university has decided to let me free," he says.
Filreis isn't looking for correct answers. He wants people to think about the poems he's teaching and engage one another.
"Poetry is really good in this setting because you can read it alone and get so much out of it, and be perfectly fine with it, but the next step was [to] hang out with some intuitively smart people and collectively — together, collaboratively — let's read the poem together," he says.
In his class this fall, Filreis will discuss poetry with a small group of students while potentially thousands make comments online. Coursera is building a system like Yelp that will let these students value each others comments; the most valued and respected will rise to the top.