Facebook has hired Alex Stamos, Yahoo's chief information security officer, as the social network's new chief security officer. Stamos was running Yahoo Mail's new end-to-end encryption service, which makes consumer emails more secure by encrypting messages in transit. "The Internet has been an incredible force for connecting the world and giving individuals access to personal, educational and economic opportunities that are unprecedented in human history," Stamos blogged. "These benefits are not without risk, and it is the responsibility of our industry to build the safest, most trustworthy products possible."