We communicate to convey meaning into understanding and not by what we are; communication without understanding is more or less junk of message. In view of this, this paper was conceived and born to review diffusion network of an innovation in a social system. It also interested us to know that the roles of opinion leader are essential to diffusion of ideas in a social system. However, an opinion leader in a particular field may be an intruder in another field of events. Therefore, an opinion leader is not a master of all. More so, this review keeps the readers abreast with the diffusion of innovations, some models of mass communication, homophily and heterophily, characteristics of opinion leader, and how they could be applied to reach the end users.
Keywords: Diffusion Network, Opinion Leaders
