According to the Wikipedia article on standard streams, The keyboard is connected to a program via standard input. I'm assuming the program refers to a shell, which interprets the commands inputted by the keyboard. My question: How are my inputs displayed on screen if they redirected to a program? Hopefully you can correct me for any misunderstanding I may have.
Your inputs are displayed to you by the terminal / program / operating system / host. If it is configured not to do so, you will see nothing on your screen.
http://en.wikipedia.org/wiki/Echo_(computing) is probably the lecture you want next.