Two years old with over 400 million daily “snaps,” the ephemeral-photo sharing company surprised its northern competitors by snagging such high-caliber talent. White’s new role at Los Angeles-based Snapchat is the latest in a string of promotions (before joining Instagram in April, she headed Mobile Business Development and Partnerships at Facebook), as well as a big risk.

Snapchat’s business model remains a question mark. It recently turned down Facebook’s reported $3 billion bid, yet the app doesn’t have an ad platform. It launched “Stories,” snaps that can be shared with all your friends for 24 hours, in October. The new feature is perhaps a precursor to its ad-sharing strategy, but that’s to be determined. Much like her early days at Instagram, White’s tasked with transforming an enthusiastic group of kids into moneymaking young professionals.

White rarely shies away from the unknown. At Fortune’s Most Powerful Women Summit in October, she recalled her 2010 move from Google (GOOG), where she was director of its emerging businesses, to Facebook. She had just delivered her first child, and maternity leave gave White the chance to ask herself, “Is this really where I want to spend the next 10 years of my career?” Friends and colleagues suggested she hold off on any big changes. “You’ve had enough change in your life,” they told her. “Don’t change the company that you work at, the people you work with, or the space that you work in … all at once. It’s just way too much change, especially when you’ve just had a baby.” She took a job heading Facebook’s local business, which changed not just one, but all three of those areas. “That was the beginning of the next chapter of my career.”

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Her time at Facebook honed an expertise in harnessing and monetizing digital communities. After leading local for a little over a year, White focused on integrating ads into Facebook’s mobile platforms. She then joined Instagram, working with founder and CEO Kevin Systrom to seamlessly blend ads into users’ photo feeds. Initially, both received uproarious pushback, but the communities seem to quickly (begrudgingly) accept the ads and only grumble from time to time. White’s also on the board of Lululemon Athletica , a retailer obsessed with engaging its customers via grassroots community events. Snapchat’s “communities” are small, high-quality groups of friends, and user interactions are one-on-one, creating a new kind of community for White (and advertisers) to study and understand.

As a structured goal-setter, the tech exec shouldn’t be too intimidated by Snapchat’s uncharted future. Lululemon requires all employees to create one-, five-, and 10-year plans outlining their health, professional, and personal goals. One of White’s was to have second baby — “I checked that box off,” she told Fortune in August — and another was to up her workout regime and begin racing. Though Fortune didn’t get a glimpse of her actual goal sheet, which hangs in the Lululemon Headquarters lobby, it’s safe to assume there was something on there about becoming the COO of a young, hot tech company. Looks like White can check off one more box.

In the video below, White dishes on how she helped structure Instagram’s business, how her time at Facebook prepared her to work with the mobile-heavy app, and what advice Sheryl Sandberg gave her about working with a founder:

[youtube=http://www.youtube.com/watch?v=yiWGZuHASyk&w=560&h=315]