Interesting! And yes, it's even in the Chronicle of Higher Education.
I'm a big fan and advocate of making lectures and lessons available (See Academic Earth, for instance.).
Of course, the caveat is that you must have a "caveat emptor/lector" approach to the source of whatever lesson you get online. There are plenty of qualified instructors out there, but there also plenty of idiots. Sometimes the idiots even have Ivy League degrees. (Whoops, did I say that out loud?) We can talk about "amateurs-vs.-professionals" later.
You know, I've always thought it'd be an absolute hilarious hoot if I gave mini-lectures online about history or literature or whatever I happen to be nerd-obsessing about at the moment, but that would mean giving up my cherished facelessness, and as Max said in the first "Mission: Impossible" movie, "I don't have to tell you what a comfort anonymity can be in my profession ... like a warm blanket." Maybe someday, when Nerd Lords aren't quite as able to shoot me down in a massive blaze of glory?