Researchers at MIT and the Korea Advanced Institute of Science and Technology, modeling the diffusion of social contagion by studying the spread of Twitter from 2006 to 2009, have found that “the site’s growth in the United States relied primarily on media attention and traditional social networks based on geographic proximity and socioeconomic similarity. In other words, at least during those early years, birds of a feather flocked — and tweeted — together.”

“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, who is co-author of a paper on this subject appearing this month in the journal PLoS ONE. “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 U.S. anyway, space and similarity matter.”

In other words, the more things change, the more they stay the same…