Jan Koum is a Ukrainian-born American internet entrepreneur who co-founded the mobile messaging application WhatsApp with Brian Acton. The extremely popular mobile application was acquired by Facebook Inc. in 2014 for a whooping US$19 billion. A billionaire today, he is counted amongst the richest Americans but just a few years ago he was so poor that he had to live off food stamps. Born into a humble family in Ukraine, he migrated to the United States as a teenager with his mother and grandmother. His initial years in the new country were very difficult; the family struggled to make ends meet. Their situation worsened when his mother became ill with cancer and eventually passed away. A resilient soul, Jan Koum worked his way through high school, and found a job at Yahoo as an infrastructure engineer, while still attending college. He formed a rapport with Brian Acton, another Yahoo employee with who he would form a long-term collaboration in future. After working at Yahoo for several years, both Koum and Acton left the job to explore newer avenues in social media. Their love for social media ultimately led the two men to form WhatsApp as a mobile messaging application which went on to become the most popular messaging platform in the world.