The Courtship, The Secret Meetings, The $19 Billion Poker Game This story appears in the March 24, 2014 issue of Forbes. C WhatsApp cofounder — and new billionaire — Jan Koum   “Get together?” The subject line of the e-mail was like every other come-on that hit Jan Koum’s in-box in the spring of 2012. He was pounded daily by investors who wanted a piece of his company, WhatsApp. Hatched on his birthday, Feb. 24, 2009, WhatsApp was emerging as a global phenomenon. Some 90 million people were using it to text and send photos for free. No social utility had ever grown … Continue reading Inside The Facebook-WhatsApp Megadeal: