If the baritone extolling the virtues of Kraft’s “homestyle” macaroni and cheese in a new commercial sounds familiar, that’s because it belongs to Ted Williams — aka “the man with the golden voice.”

A former radio announcer who fell on hard times and became homeless due to problems with drugs and alcohol, Williams was panhandling on the side of a highway in Columbus, Ohio when his talent was discovered by a local newspaper reporter. The video in which Willliams demonstrated what he called his “God-given gift of voice” quickly went viral.

Millions of YouTube views later, Williams was featured on the Today show and Late Night with Jimmy Fallon. He also got job offers from the Cleveland Cavaliers, MSNBC and Kraft. The mac & cheese commercial showcasing Williams’ deep baritone aired for the first time during the Kraft Hunger Bowl on Sunday:

http://www.youtube.com/watch?v=Dy85lAKLasw

The rags to riches story is spawning plenty of spin-offs, including pieces on whether the sudden onslaught of fame could be damaging for Williams.

What made Williams’ story go viral? Recent research by Wharton professors Jonah Berger and Katherine Milkman may provide some answers. Using data from nearly 7,000 New York Times articles published on the paper’s website in a three-month period, they looked at how emotion plays into sharing content and the types of stories that are more likely to make the Times‘ “most e-mailed” list.

“Transmission is about more than simply sharing positive things and avoiding sharing negative ones,” Berger and Milkman write. They say content that stirs up a stimulating emotion in people, such as awe, anger or anxiety,  is more viral. Content that prompts what the researchers term a “low arousal” emotion — like sadness  — is less viral. This emotional connection to virality existed even after the professors accounted for other factors, like the usefulness of the information presented or the story’s prominence in the paper or on the Times website.

Longer stories, stories penned by well-known writers and stories authored by women were also more likely to make the most e-mailed list. Even in sections more likely to contain articles that provoked a strong emotion — such as the health or opinion pages — highly surprising and awe-inspiring stories stood out to readers and consequently were more likely to go viral. The odds of making the most e-mailed list increased the most when a story generated feelings of anger or awe.

Overall, Berger and Milkman say that positive content — like the rags-to-riches story of Williams — is more likely to be shared. “Together these findings shed light on why people share content, provide insight into designing effective viral marketing campaigns and underscore the importance of individual-level psychological processes in shaping collective outcomes.”