3 Silicon Valley execs who could replace Microsoft's Ballmer

Steve Ballmer, CEO of Microsoft Corp., announced Friday that he would retired within 12 months. Now the question on everybody's mind in the tech community is, who will replace him? It's unlikely Ballmer's successor will come from outside Microsoft's Redmond headquarters, but should the company feel like scouting Silicon Valley, we've got a few interesting candidates to lead the software behemoth...