1) It’s an ingenious solution to the snow-plow-knocking-over-the-mailbox problem: mount the mailbox on a spring to absorb the impact of the plowed snow. I’ve seen several mailboxes like this, so this photo is a tribute to all of them.
2) It’s resourceful. The springs used for this type of mailbox all seem to have been salvaged from old pieces of farm equipment.
3) It’s visible in the previous weather station photo.