"The estimates suggest that the shift to Internet sales substantially increased both seller profits and consumer surplus."

The finding from a new NBER working paper by Glenn Ellison and Sara Fisher Ellison titled, "Match Quality, Search, and the Internet Market for Used Book."

Abstract:

This paper examines the effect of the Internet on markets in which match-quality is important, including an analysis of the market for used books.  A model in which sellers of unusual objects wait for high-value buyers to arrive brings out match quality and competition effects through which improved search technologies may increase both price dispersion and social welfare.  A reduced-form empirical analysis finds support for a number of more nuanced predictions of the model in the context of the used book market, exploiting both cross-sectional differences across books and time-series differences in the wake of Amazon's acquisition and incorporation of a large used book marketplace.  The paper develops a framework for structural estimation of a model based on the theory.  The estimates suggest that the shift to Internet sales substantially increased both seller profits and consumer surplus.