The MIT Technology Review just published a great post on the physics arXiv blog that covered some recent research from Maksim Kitsak et. al. that found that the best connected individuals are NOT the most influential spreaders in social networks.
In a social network, most of the nodes (people) are not linked to each other, but most can still be reached by a small number of steps, according to the small worlds network theory. (In fact, recent research indicates that the average separation is now less than 5, and not 6.) In these networks, some nodes are much better connected than others. Traditional thinking is that these so-called hubs play a correspondingly greater role in the way information and viruses spread through a society. But traditional thinking has just been proved wrong!
Kitsak et. al have found that in contrast to common belief, the most influential spreaders in a social network do not correspond to the best connected people or to the most central people. This might seem counterintuitive, but, on reflection, it does make perfect sense. For example, many of the “best connected” people typically exist on the edge of the network, and, as a result, have minimal impact on the spreading process through the core of the network. In contrast, “a less connected person who is strategically placed in the core of the network will have a significant effect that leads to dissemination through a large fraction of the population“. Or, in other words, it’s not how many hits a site gets, it’s who hits the site. There are influencers and followers. If most of the readers hitting a site are followers, the message will not get spread beyond those readers. But if most of the readers are hitting a site are influencers, the message will spread far and wide with only a fraction of the hits!