Jupiter's David Card is not buying into the post-Radiohead hype that all music is yearning to be free. "Armchair economists, please stay home," he exclaims in reaction to a TechCrunch post about digital music's near-zero marginal cost of production. "By this remarkably oversimplified analysis, software, filmed entertainment, soda at McDonalds, and the classic example, high-end perfume, should all be free."

He's right. People throw around the term marginal cost as if average cost never existed and there is no such thing as a break-even point. (That publicist that was required in order for those computer programmers to ever hear of that artist? She cost a pretty penny. Studio time tends not have a zero marginal cost, either.)

The Zero Marginal Cost crowd insists increased revenue from touring and merchandise can pay for all this free music. But that would create a huge free rider problem in which consumers push onto the most active fans the responsibility of supporting the artist. How about if that zero-marginal-cost music is given away for free at the concert only? Given how seldom the typical American leaves the house to see live music, paying for music would start making a lot more sense. (I won't even get into how this wouldn't even make sense for artists who cannot or choose not to tour.)