Why Hello world?

Question

Why people do "Hello World!"as their first program always?

Answer 1

According To Me
They do this to say Hello To the New World that is
"Programming World"
Almost everyone's first program is Hello World.
Also It is The First Program as it is the easiest way to get to know how that language works.

Answer 2

The most basic concept and the first topic that you learn in most languages is knowing how to print text on the screen. It is something that you will need constantly, and for that reason that example of adapts perfectly.

NOTE: I said most of the languages because in functional languages other subjects are usually treated before, since any function that prints text on the screen is considered non-pure (that is, it is a function with side-effects)