What programming languages use the most favorite sites?

Question

I would like to know what programming languages do the most famous and lucky sites use in order to understand the consensus of todays technology (at lease for several examples). What languages use the following sites?

1. Google
2. Yahoo
3. Facebook
4. YouTube

Is the language choice depend on the time when they have started to develop their projects or the languages that they use best fits to the profile of the project?

Answer 1

From what I know:

• Google: Java, C++, Javascript, Python
• Facebook: PHP, Javascript, C++
• YouTube: PHP, Java, Python, Javascript
• Yahoo: Javascript, Perl, and probably Java (not sure)