Ironically, Twitter use took off across the US bacause of traditional face-to-face interaction, an MIT study shows.
Researchers studied the growth of Twitter from its launch in 2006 to 2009, examining data from 16,000 US cities and focusing on the 408 with the highest number of Twitter users.
And, they say, the site’s growth in the relied mainly on traditional social networks based on geographic proximity and socioeconomic similarity, as well as on media attention.
They looked in particular at when cities reached 'critical mass', with 13.5 percent of residents being Twitter users.
As you might expect, the growth in popularity initially spread via young, tech-savvy 'innovators' - in this case from Twitter’s birthplace in San Francisco to greater Boston.
But the next areas to reach critical mass tended to be only short distances away, implying face-to-face interactions: Somerville, Massachusetts, and Berkeley, California were both early adopters, for instance.
Cities such as Palm Beach, Florida, and Newark, New Jersey were amongst the last of the 408 cities to hit critical mass.
"Even on the internet, where we may think the world is flat, it’s not,” says Marta González, assistant professor of civil and environmental engineering and engineering systems at MIT.
"The big question for people in industry is ‘How do we find the right person or hub to adopt our new app so that it will go viral?’ But we found that the lone tech-savvy person can’t do it; this also requires word of mouth. The social network needs geographical proximity. In the US, anyway, space and similarity matter."
MIT's model of Twitter contagion didn’t quite fit the data, though, until the team added media influence, based on the number of news stories appearing weekly in Google News searches.
"Other studies have included news media in their models, but usually as a constant,” González says. “We saw that news media is not a constant. Instead, it’s media responding to people’s interest and vice versa, so we included it as random spikes."
Watch Twitter spread across the US, below.