In November 2006, Mignon Fogarty’s phone rang. She didn’t recognize the number, but rather than letting it go to voicemail, as many of us do with unknown callers, she picked up. On the other end of the line was John Sterling, the president and publisher of Henry Holt, an imprint of Macmillan. He’d seen a recent item in the Wall Street Journal about Grammar Girl, a hit podcast Fogarty had launched a few months prior that was already receiving nearly a hundred thousand downloads per episode. “He originally called me to talk about doing a book deal,” she told me. But she had already set her sights much higher.