Facebook does not use any meaningful amount of D. Source: I worked at Facebook for four years. My first diff at Facebook was even in D, in a project that was a

Facebook does not use any meaningful amount of D. Source: I worked at Facebook for four years. My first diff at Facebook was even in D, in a project that was already effectively abandoned by the time I changed it. It's really a tiny, insignificant minority of actively running code there, possibly zero by now.