What programming languages ​​should be known for creating something like Facebook?

Question

What did Mark Zuckerberg need to know before starting his small project, which has become a huge worldwide application with over 1 billion users?

Answer 1

HTML, CSS, JavaScript, PHP, mySQL, Shell Command.

A hosting platform, a database, a server & an idea!

That's it. You would be ready if it were 2004 but it's not 2004 and so the above mentioned technologies are only prerequisites of some kind(well, at least the first three). Now, there are frameworks which you ought to know in today's world i.e React.js, Angular.js(front) / Node.js, Ember.js(back). You should also try Python! Learn to use GIT or any version control system. Master in shell scripting. Learn little bit about networking. Then I think you'll be able to build something like Facebook(or maybe better!)