Chris Blattman in Internet versus live lectures: Live lectures win links to a paper Is it Live or is it Internet? Experimental Estimates of the Effects of Online Instruction on Student Learning which indicates "…we find modest evidence that live-only instruction dominates internet instruction." one of the comments "I just skimmed the paper but I think the results helps the case for internet lectures.
1. The marginal cost of an internet lecture is smaller, and the difference in costs is (probably) higher than the difference in benefits. So internet wins.
2. Internet lectures allow high quality teachers to teach more students. This effect is likely to be important ( my guess). The paper does not address that, but this is the main advantage of internet lectures."
Internet learning comesin many forms and it seems to me that one of the main adavantages is that one can learn at one' own pace and at atime in surroundings of one's choice.
Seealso The Outlook story about the Khan Academy and Physorg story Mobile learning with iPhone now possible.