No, they aren't. Quote Adam D'Angelo, former CTO of Facebook: "PHP was out of the question [for building Quora]. Facebook is stuck on that for legacy reasons,

No, they aren't. Quote Adam D'Angelo, former CTO of Facebook: "PHP was out of the question [for building Quora]. Facebook is stuck on that for legacy reasons, not because it's the best choice right now". (source: http://www.quora.com/Quora-Infrastructure/Why-did-Quora-choose-Python-for-its-development/answer/Adam-DAngelo http://www.quora.com/Quora-Infrastructure/Why-did-Quora-choo...)