But something strange happened in the 20th century, when that wavelike form of spreading seemingly vanished. Air travel suddenly allowed diseases to jump from one continent to another at breakneck speed. However, network theorists found they could restore the wavelike nature of the spread if they account for the speed of travel. By normalizing the spread in this way, a wavelike spreading pattern reemerges.
Social phenomenon, such as songs, tweets, videos, and so on, are thought to spread in a similar way. And because this happens from person to person through a social network, it should follow a wavelike spreading pattern.
But observing this pattern is hard because the geographical spread of information is distorted by the social media networks along which it moves. And that raises the question of whether it is really wavelike or fundamentally different.
To solve this conundrum, network scientists would dearly love to have an emblematic example of the way a specific piece of information has spread across the globe in a measurable way.
Today, Zsofia Kallus and pals at Eotvos University in Budapest, Hungary, say they have found just such an example in the way that Psy’s Gangnam Style video spread across the globe in 2012, eventually becoming the first to receive over a billion views on YouTube. And the team say it is possible to recover the unique wavelike signature of information spreading, providing they properly take account of the social networks involved.
The story behind this video pandemic is extraordinary. This music video was produced in a style known as k-pop by a South Korean musician called Psy, who was relatively unknown outside his home country. It was released on July 15, 2012, and immediately become popular in South Korea.
But since Psy was unknown outside the country, the video’s later success was hard to predict. By December 21, 2012, however, the video had become the most viewed in history when it reached a billion views of YouTube across the globe. “In 2012, the record breaking ‘Gangnam Style’ marked the appearance of a new type of online meme, reaching unprecedented level of fame despite its originally small local audience,” say Kallus and co.
Just how this happened is the focus of Kallus and co’s work. To do this, they tracked the spread of the video by searching the historical Twitter stream for geolocated tweets that mention “Gangnam Style.” “Location information allows us to record the approximate arrival time of a certain news to a specific geo-political region,” say Kallus and co.
