And you may not miss the "HipHop for PHP", an open source PHP to C++ translator, that allows Mr. Zuckerberg and his team to write their code in good old PHP and still be as efficient as a hightly optimized C++ code, while they have time to enjoy the biliions of dollars they're earning. To develop HipHop, Facebook has hired some of the best compiler develpers in the world, and they made it open source since 2010. It it propably the heart of all Facebook technology.