Facebook also uses a very restricted subset of php for a lot of it, if the people I've met from over there are any indication. This may make it generally more u

Facebook also uses a very restricted subset of php for a lot of it, if the people I've met from over there are any indication. This may make it generally more useful for them than it may normally be. I think they have to use that subset so it can be compiled by HipHop down to C code.