For creating a website like "Facebook" which programming languages need?

Answer 1

Mostly you'll need PHP and SQL, but some Java and C++ would be nice because Facebook uses HipHop to convert PHP into C++ .
and OF COURSE you'll need Linux knowledge

Answer 2

The programming languages aren't important. To be able to create a website at a scale as Facebook, you'll need to be very good at software architecture. Facebook was initially written in PHP.

Answer 3

php must..