When South Korean pop star Psy released his “Gangnam Style” video in 2012 it spread like wildfire. Researchers at Indiana University Bloomington tracked the spreading meme by following how Twitter users shared the video with friends and strangers alike. By the time 200 tweets had linked to the video among the subset of Twitter users studied, “Gangnam Style” had already reached 86 different communities of users (blue nodes). After 3,000 tweets the meme had spread to nearly 1,000 different communities (green). “Gangnam Style” soon became the most-viewed video in YouTube history; by late 2013, the video had amassed more than 1.8 billion views.

Graphic by Jan Willem Tulp, for Scientific American
SOURCE: Lilian Weng (Companion data set to “Virality Prediction and Community Structure in Social Networks,” By Lilian Weng, Filippo Menczer and Yong-Yeol Ahn, in Scientific Reports, Vol. 3, Article No. 2522; August 28, 2013)

More in this Article: See how Twitter Trends Help Researchers Forecast Viral Memes.