Complements, substitutes or sweet spots?

I understand the Baumol Cost Disease story, but am not sure I buy it. It's a cinch that we can now enjoy more and better music in the home than ever. Technology does augment the reach and productivity of all those string quartets.  Uneven productivity advances are normal.

I have previously blogged about our fine experiences enjoying the Berliner Philharmoniker at home.  We recently found Jewish High Holy Day services on the net which were splendid.  I was pleasantly surprised.

Substitutes or complements?  Some people like their beer and bourbon together and others think of an interlude with one or the other.  As always, it is all about subjective and personal choices.

MIT President Rafael Reif writes about "What Campuses Can Learn From Online Teaching ... Searching for the sweet spot where cyberstudents around the world pay a small fee that helps make the 'residential' college more affordable" in today's WSJ.  Are the two modes substitutes or complements?  I am a great believer in the idea that competition breeds experimentation which breeds discovery.  Sweet spots will be found.

I have been looking at on-line courses for years.  Some are awful and some are pretty good.  It is no surprise that Marginal Revolution University looks very good.  Many will be looking for the "sweet spot" whereby this freeby complements their teaching.