One of the more thoughtful vectors into the free-versus-pay content debate is a recent post by Michael Erard on the future of attention, how its value might be calculated, and how cultural products might then be priced.
Erard's imagination lets loose and he contemplates taxes, prices and retail sectors built around one's ability to pay (grant) attention, including software that audits your attention (deficit) and accords a fee.
The practical application of the concept is on the debate we're now involved in --- the one that assesses a marketable value on the content created and consumed.