Sandberg’s vision of Facebook as a mobile advertising giant is finally becoming a reality. ­Facebook’s profits nearly doubled in 2014, to $2.9 billion, and mobile ad revenue now comprises 76% of its total ad sales, up from 62% in the second quarter of 2014. The next chapter in Sandberg’s monetization strategy involves attracting more advertisers to viral photo-sharing app Instagram, which now counts 300 million users. Facebook is also moving to capitalize on the social network’s 4 billion video views a day. In May, Sandberg suffered the tragic loss of her husband, technology executive Dave Goldberg. She took his seat on the board of his company, SurveyMonkey, in July.