TITLE: COFOUNDER, WHATSAPP
IMPACT: JAN KOUM GREW UP IN THE SOVIET UNION WITHOUT RUNNING WATER. After he and his mother immigrated to Mountain View, Calif., in 1992 when he was 16, they lived off food stamps. But Koum’s luck started to change when he enrolled at San Jose State University to study computer science and then went to work for Yahoo. In 2009, he cocreated WhatsApp. The mobile messaging app is now one of world’s most used—handling billions of messages every day—and is particularly important in the developing world. Facebook bought WhatsApp in 2014 for $19 billion. Just months after the sale, Koum paid it forward: He donated $556 million to the Silicon Valley Community Foundation, which funds approximately 18,000 charities in the Bay Area.