Defining a variable with or without export

Question

What is export for?

What is the difference between:

export name=value

and

name=value

Answer 1

To illustrate what the other answers are saying:

$ foo="Hello, World"
$ echo $foo
Hello, World
$ bar="Goodbye"
$ export foo
$ bash
bash-3.2$ echo $foo
Hello, World
bash-3.2$ echo $bar

bash-3.2$