By nearly any measure, Facebook has had a remarkable year. More than 1.65 billion people use the service every month, making it the world's largest social network by a considerable margin. Its advertising business has grown significantly faster than analyst expectations, powered by sophisticated targeting capabilities that rivals struggle to match. And in April, CEO Mark Zuckerberg laid out an ambitious 10-year vision that places the company at the frontier of computer science, making aggressive moves in bringing artificial intelligence and virtual reality to the mainstream.