The ease-of-influence factor (10 Jan 2008)

Science News reports about a study testing the influence of opinion leaders, busybody extroverts eager to share recommendations with a wide network of people. Somewhat surprisingly, the researchers Duncan Watts and Peter Dodds found with computer simulations that a critical mass of easily influenced people is more important for the spread of an idea rather than super proselytizers.

More important than the influencers, the researchers found, were the influenced. Once an idea spread to a critical mass of easily influenced individuals, it took hold and continued to spread to other easily influenced individuals. In some networks, it was far easier to get an idea established this way than in others. The entire structure of the network mattered, not just the few influential people.
Dodds compares the spread of ideas to the spread of a forest fire. When a fire turns into a conflagration, no one says that it was because the spark that began it was so potent. "If it had been raining," Dodds says, "that same match wouldn't have had an effect." Instead, a fire takes off because of the properties of the larger forest environment: the dryness, the density, the wind, the temperature.
The upshot of the study, Dodds says, is that "in the end, you don't have control over how people spread your message." The best way to increase the odds of person-to-person transmission of an idea is to make it a good idea and to give it "social worth," he says. "Some things are just fun to talk about."

Ideas, then, are subject to network effects -- the notion that the size of a phenomenon creates its own exponential positive feedback -- and their spread has even less to do with their intrinsic quality. What helps spread an idea is not some Tipping Point style special influencer but the ability to bring a large group of naive and easily persuaded people with a propensity for novelty for its own sake into contact with one other -- say, some site that would get a bunch of teenagers together to do little other than share and reaffirm one another's preferences. I wonder if some clever college dropout will come up with such a thing.