Watts going on with social contagion?

Diffusion in social networks (social contagion) is still one of the hot topics in IS and networks. What do we really know about social contagion and diffusion of trends, norms or product use? Duncan Watts says 1) we know little, 2) almost nothing really diffuses far in online settings, and 3) models of diffusion should integrate individual characteristics of the adopters. Great morning read. Looking forward to reading responds from the marketing and social media side to both papers!