Yahoo's Marissa Mayer: Hail to the Chief by Jacob Weisberg | photographed by Mikael Jansson As she works to reverse the fortunes of a failing Silicon Valley giant, Yahoo’s Marissa Mayer has fueled a national debate about the office life, motherhood, and what it takes to be the CEO of the moment. “I really like even numbers, and I like heavily divisible numbers. Twelve is my lucky number—I just lov