We consider the diffusion of new products in social networks, where consumers
who adopt the product can later "recover" and stop influencing others to adopt
the product. We show that the diffusion is not described by the SIR model, but
rather by a novel model, the Bass-SIR model, which combines the Bass model for
diffusion of new products with the SIR model for epidemics. The phase
transition of consumers from non-adopters to adopters is described by a
non-standard Kolmogorov-Johnson-Mehl-Avrami model, in which clusters growth is
limited by adopters' recovery. Therefore, diffusion in the Bass-SIR model only
depends on the local structure of the social network, but not on the average
distance between consumers. Consequently, unlike the SIR model, a small-worlds
structure has a negligible effect on the diffusion. Surprisingly, diffusion on
scale-free networks is nearly identical to that on Cartesian ones.Comment: 5 pages, 5 figure