Felten's Grand Unified Theory of Filesharing

On "Freedom to Tinker," Ed Felten writes:

Recently we've seen several studies of the impact of filesharing on CD sales. We have enough data now to draw some (very) preliminary conclusions, assuming the studies are correct. Despite the apparent contradictions between the various studies, I think there is a plausible theory that can explain them all — a Grand Unified Theory of Filesharing.

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