For anyone interested in the spread of information among a human population, it is important to understand whether there are individuals who exert more impact on the knowledge, perceptions, and behavior than others. Social scientists interested in the causes of social change can find root causes in the existence, number, and behavior of influentials. The rapidly growing number of researchers interested in social networks can add another explanatory variable to the array of “physical” constraints of network structures. For marketers, politicians, and activists interested in actionable strategies, targeting influentials could increase the efficiency of their campaigns.
Despite the large interest and extensive research in this topic area, there are still fundamental questions that have not been answered: Do influentials exist, and what defines them? Do explanations of social phenomena such as diffusion of innovations, informational cascades, and public opinion formation need to assume the existence of influentials, or can those processes be modeled and explained without the use of influentials, as Duncan J. Watts and Peter S. Dodds have recently claimed? If so, are there conditions under which influentials are more important than other variables that define a social network?