Sandberg on Facebook: 'We are our own biggest risk'

Sheryl Sandberg, Fortune Brainstorm Tech marketing dinner New York 2014 (Credit: Photograph by Rebecca Greenfield/Fortune Brainstorm Tech)

Near the top of Facebook's most recent annual report—which, I should warn you, runs nearly 100 pages long—the social networking company (FB) outlines its biggest business risks. The first is a tenet of any firm that dares to describe itself with the "s" word. "If we fail to retain existing users or add new users, or if our users decrease their level of engagement with Facebook," it reads, "our revenue, financial results, and business may be significantly harmed." Read a bit further and you'll come across the second biggest risk to Facebook's business. It reads: "We generate a substantial majority of our revenue from advertising. The loss of marketers, or reduction in spending by marketers with Facebook, could seriously harm our business." Substantial, if you're wondering, is 89% of the almost $8 billion it took in last year. It is this reason why Sheryl Sandberg, the company's chief operating officer, was in New York this week. Sandberg, of Lean In fame, was in town for the city's annual Advertising Week. On Sunday, her company announced that it had rebuilt Atlas, an advertising software suite it bought from Microsoft