We study how opinion leadership and social contagion within social networks affect the adoption of a new product. In contrast to earlier studies, we find evidence of contagion operating over network ties, even after controlling for marketing effort and arbitrary systemwide changes. More...

Building on the commentaries on our work, we make additional suggestions for future research on social contagion and new product diffusion. In particular, we note that social contagion may occur for many reasons and that investigating how various personal or group characteristics moderate the...

We model the diffusion of innovations in markets with two segments: who are more in touch with new developments and who affect another segment of whose own adoptions do not affect the influentials. This two-segment structure with asymmetric influence is consistent with several theories in...

Standard diffusion models capture social contagion only coarsely and do not allow one to operationalize different contagion mechanisms. Moreover, there is increasing skepticism about the importance of contagion and, as has long been known, S-shaped diffusion curves can also result from...