Top college courses, for free?

By Daphne Koller, Special to CNN

Editor's note: Daphne Koller is Rajeev Motwani Professor in the Computer Science Department at Stanford University and co-founder and co-CEO of Coursera. She is the recipient of awards including the Presidential Early Career Award for Scientists and Engineers and the MacArthur Foundation Fellowship. Koller spoke at the TED Global conference in June in Edinburgh. TED is a nonprofit dedicated to "Ideas worth spreading" which it makes available through talks posted on its website.

(CNN) - Almost exactly a year ago, Stanford University took a bold step. It opened up an online version of three of its most popular Computer Science classes to everyone around the world, for free.

Within weeks, close to 100,000 students or more were enrolled in each of these courses. Cumulatively, tens of thousands of students completed these courses and received a statement of accomplishment from the instructor. This was a real course experience. It started on a given day, and the students would watch videos weekly and do homework assignments. These were real homework assignments for a real grade, with a real deadline.

One of those classes was taught by my co-founder, Andrew Ng. In his on-campus Stanford class, he reaches 400 students a year. It would have taken him 250 years to reach the number of students he reached through that one online course.

The Stanford endeavor showed what is possible. It showed that it is possible to produce a high quality learning experience from some of the top instructors in the world at a very low cost.