Is it the same programming language which which was used to write Facebook, google or twitter?

Answer 1

Google and Facebook are now very large enterprises that maintain huge codebases in C++, Java, Python and many other languages. However, as MrCoder indicates, Facebook started as a PHP app. And Twitter started as a Ruby shop.

Once a company reaches a certain size, it makes more financial sense to build highly optimized stuff in C++.

Answer 2

Facebook: PHP
Google(Chrome?): C++ but shifted to Go I think?
Twitter: Ruby

Answer 3

Yeah, those companies use everything under the sun. Twitter is known for its Scala usage, too.

Large companies often switch to type safe languages and compiled languages. C++ doesn't have much of a role in web services.