The first post has to be the ubiquitous Hello World.

A bit of history

“Hello, World” was created by Brian Kernighan, author of one of the most widely read programming books: C Programming Language, in 1978. He first referenced ‘Hello World’ in the C Programming Language book’s predecessor: A Tutorial Introduction to the Programming Language B published in 1973.

main( )
  extrn a, b, c;
  putchar(a); putchar(b); putchar(c); putchar(’!*n’);
 a ’hell’;
 b ’o, w’;
 c ’orld’;

What I do remember is that I had seen a cartoon that showed an egg and a chick and the chick was saying, “Hello, World.” - Brian Kernighan

By 銀糸 - Self-photographed, Public Domain, Link