You could make your point even stronger: since the barriers to entry on the internet are so low, it has the potential to be a lot less intellectually constraining than an ordinary classroom, where typically there will be one teacher, with standardized lesson plans, teaching from a relentlessly bland textbook that passed through the censors in Texas and California.
But the Internet also has a significant winner-take-all character at the large end of the spectrum, due to network effects. See Facebook vs. MySpace and all the other social network carcasses in its wake. Mr. Khan's teaching videos might end up being the one-and-only source of education on the Internet. What then?
Then you can make your own better video and YouTube or Khan itself will host if for free and show that what you were afraid of is not actually possible and the social networking analogy does not hold up under cursory analysis.
