As a top executive and employee number 20 at Google, there wasn't necessarily a tremendous opportunity for growth at the Mountain View search giant. That may explain Marissa Mayer's recent decision to jump ship in favor of joining Yahoo as the company's chief executive -- a role the former Google VP of Local, Maps and Location Services plans to assume tomorrow. Mayer joined Google way back in June of 1999, and was the company's first female engineer, and stayed with the company until her resignation earlier today. There's no question that Yahoo will be in good hands, but
