This special issue is created to mark the 40th anniversary of Everett Rogers' Diffusion of Innovations (DOI) model. Diffusion is the process through which an innovation, defined as an idea perceived as new, spreads via certain communication channels over time among the members of a particular social system. A great deal of research in a variety of academic disciplines (about 5000 published studies so far) has been conducted on the diffusion of innovations over the past six decades. The areas of application for these studies range from hybrid seed corn to modem math, to the snowmobile to antibiotic drugs, to HIV/AIDS prevention (Rogers, 1995). These investigations have led to a general model of the diffusion of innovations, which can be applied to the recent spread of the Internet or to any other new idea. Everett Roger's ground-breaking model has contributed to a greater understanding of behavioral change, including the variation in rates of adoption of innovations, and it has held a broad scope of practical applications in the field of public health.
