Facebook began using HipHop (their PHP compiler) at a time when they already had 200 million users and a website that by definition is very hard to cache. So in

Facebook began using HipHop (their PHP compiler) at a time when they already had 200 million users and a website that by definition is very hard to cache. So in other words, PHP without Facebook's custom compiler was able to handle a site having 200 million frequently returning users. I'd say that's pretty good. Sources: http://www.h-online.com/open/news/item/HipHop-Facebook-s-PHP-accelerator-makes-C-code-920962.html http://www.h-online.com/open/news/item/HipHop-Facebook-s-PHP... and http://en.wikipedia.org/wiki/Facebook http://en.wikipedia.org/wiki/Facebook