Earlier I wrote that the problem with online education is credentialing.  It looks like Coursera is starting to tackle issue:

Coursera recently announced another route to help students earn credit for its courses — and produce revenue. The company has arranged for the American Council on Education, the umbrella group of higher education, to have subject experts assess whether several courses are worthy of transfer credits. If the experts say they are, students who successfully complete those courses could take an identity-verified proctored exam, pay a fee and get an ACE Credit transcript, a certification that 2,000 universities already accept for credit.