What makes a meme— an idea, a phrase, an image—go viral? For starters, the meme must have broad appeal, so it can spread not just within communities of like-minded individuals but can leap from one community to the next. Researchers, by mining public Twitter data, have found that a meme's “virality” is often evident from the start. After only a few dozen tweets, a typical viral meme (as defined by tweets using a given hashtag) will already have caught on in numerous communities of Twitter users. In contrast, a meme destined to peter out will resonate in fewer groups.

“We didn't expect to see that the viral memes were going to behave very differently from nonviral memes at their beginnings,” says Lilian Weng, a graduate student in informatics at Indiana University Bloomington. Those differences allowed Weng and her colleagues to forecast memes that would go viral with an accuracy of better than 60 percent, the team reported in a 2013 study.

Graphic by Jan Willem Tulp, for Scientific American
SOURCE:“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

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