It became a place to ring a doorbell out of the rain, a place to wave to neighbors, a buffer zone between the intense activity of the outside world and the intense activity inside the house: a kind of refuge where you're not quite inside, but you're not quite outside either... the realm of the porch, a world unto itself.
The front porch serves as a transition zone from someone's home and the rest of the world. It is your personal staging area to get ready for life beyond the railing.
Here's something I wrote in 1973 to memorialize the importance of taking time on the front porch. Click on the image to enlarge the view.