If there were a poster child for the power of social media to make career dreams come true, it would be Lindsey Stirling. Her one-of-a-kind dancing-while-playing-violin performances were too offbeat for the music industry to initially get, but rather than change who she was, she took to YouTube to do her thing. Today, 7.2 million subscribers, two albums, and a world tour later, the Brigham Young grad whose parents couldn't afford dance lessons is officially YouTube's highest-earning woman, with a memoir, The Only Pirate at the Party, out this month. So how did she do it? I caught up with Stirling in New York City, where she was shooting a new video, to find out.

Stirling on the street in New York City. When an early song got a million views on YouTube, "I thought the counter was broken!" she recalls.

Cindi Leive: In 2010 you got to the quarterfinals of America's Got Talent, but Piers Morgan said, and I quote, that your music sounded like "rats being strangled." What would you say to him now?

Lindsey Stirling: I feel like I owe a lot to Piers Morgan! He gave me a reason to fight. After I had a good cry and pulled myself up by my bootstraps, that hurt and embarrassment turned into extreme motivation—"I'm gonna prove them wrong!"

CL: And you went from America's Got Talent to YouTube—how'd that happen?

LS: I was very unfamiliar with YouTube; I thought it was the place for dog and cat videos. Then [videographer] Devin Graham opened me up to this world, and I just knew it was what I was going to do. It was like, "I don't have to wait for someone else to invest in me. I can invest in myself." And Devin taught me that people don't just get viral videos; there is a strategy. One of the tools was doing things that are searchable, like cover songs. Because "Lindsey Stirling violin" was not!

CL: It was a big moment for you when you went from YouTube to live performances. Tell me about your first show, at Webster Hall in New York City.