Kevin Systrom started Instagram in 2010, when he was 26, with a guy he’d befriended in a San Francisco coffee bar. Eighteen months later, when the company was just 13 people and still without a business plan, Mark Zuckerberg came calling with an offer of $300 million in cash and $700 million in Facebook’s pre-IPO stock. Systrom said yes only after he persuaded Zuckerberg to keep the Instagram brand alive and to let him and cofounder Mike Krieger run it.

Three years later, it’s clear that the creation of Instagram was remarkably well timed and well executed. The service is like Twitter, but with pictures and videos primary rather than text. It works because people like to tell stories with pictures: it’s easy, and it has impact across languages and cultures. Instagram has more than 300 million users, who post more than 70 million photos and videos every day.

One big question still faces Systrom, though: can he turn all this attention into a real business? He started rolling out an advertising program last fall and remains coy about how it’s doing. Systrom says he just has to find a way to present the ads without upsetting his users, the vast majority of whom are younger than 30.

Systrom himself is something of a model for an emerging kind of high-tech entrepreneur, at the intersection of technology and the liberal arts. He’s a jock, having been captain of his high school lacrosse team. He’s also artistic, having effectively minored in photography while getting an engineering and management degree at Stanford. He knows the corporate world: he’s on the board of Walmart. And he’s an extrovert, as comfortable with runway models in New York and movie stars in Hollywood as he is with coders in Silicon Valley. As mobile applications and social networking permeate more of our economy, people who understand how these technologies make the physical world more interesting or productive will become as important as the hard-core engineers.

—Fred Vogelstein