So a way of finding seed groups in a given social network would surely be a useful trick, not to mention a valuable one. Step forward Paulo Shakarian, Sean Eyre and Damon Paulo from the West Point Network Science Center at the US Military Academy in West Point.
These guys have found a way to identify a seed group that, when infected, can spread a message across an entire network. And they say it can be done quickly and easily, even on relatively large networks.
Their method is relatively straightforward. It is based on the idea that an individual will eventually receive a message if a certain proportion of his or her friends already have that message. This proportion is a critical threshold and is crucial in their approach.
Having determined the threshold, these guys examine the network and look for all those individuals who have more friends than this critical number. They then remove those who exceed the threshold by the largest amount.
In the next, step, they repeat this process, looking for all those with more friends than the critical threshold and pruning those with the greatest excess. And so on.
This process finishes when there is nobody left in the network who has more friends than the threshold. When this happens, whoever is left is the seed group. A message sent to each member of this group can and should spread to the entire network.
More here. The key breakthrough for the researchers was not trying to force themselves to find the smallest possible seed group. This feels like it will be the seed, pun intended, of a Malcolm Gladwell article. Maybe the sequel to The Tipping Point.