Before launching the billion-dollar media company BuzzFeed, Jonah Peretti's life looked pretty normal: He graduated from UC Santa Cruz with a degree in environmental studies and landed a teaching job in New Orleans. Then an email squabble with sports apparel giant Nike piqued his interest in viral media. He spent three years teaching computer science before heading to MIT to get his master's. It was there that Peretti first started thinking about how ideas spread, why people share things and the media industry in general — but not because of a specific class or professor. In 2001, towards the end of his time at MIT, Peretti was procrastinating. "Someone told me that Nike had launched a service where you could customize your shoes, which was a new novel thing," Peretti tells Guy Raz at a live taping of NPR's podcast "How I Built This." Rather than working on his master's thesis, Peretti decided to see what words the system would allow him to put under the Nike swoosh: "I first tried a four letter word and it rejected it, and so I was trying to figure out how the system worked. They had blacklisted a bunch of words. ... And then I put the word 'sweatshop' in, and it went through."

Jonah Peretti speaks to Guy Raz at a live taping of NPR's "How I Built This" in New York City Courtsy of Ebru Yildiz/NPR

The next day, Peretti got an email from Nike rejecting the order and "saying the word 'sweatshop' is inappropriate slang," Peretti tells the audience in New York City: "I just responded ... and said: 'No, it's in the dictionary. It means a shop or factory where workers toil around in unhealthy conditions. Now can you send me the shoes?'" After a series of back-and-forth emails, in which Nike continued to reject the order, Peretti pasted the correspondence together and sent it to a few friends. At a time when the concept of "going viral" didn't yet exist, his creation became an early email forward and ended up reaching millions of people. Peretti's email spread so widely that, despite knowing little about the sweatshop issue, "I ended up on the Today Show with Nike's head of global PR and Katie Couric talking about sweatshop labor," he tells Raz. He starting asking himself, "How can a student with no context in the media reach millions of people about an issue he knows very little about?" Ultimately, the viral Nike email put Peretti in contact with Ken Lerer and Arianna Huffington, with whom he founded the Huffington Post in 2005.