tl;dr proposal: Google Voice for postal mail. The USPS assigns you a unique ID, you tell them where to forward that ID, and they can't disclose who it belongs to or where it goes without court process or your permission. You could get mail that's just addressed to "PAF 13JS-00EG-C, United States", and it'd automagically get routed to you. You can also choose to give UPS, FedEx, etc permission to access the forwarding info if you want.
tl;dr benefits: Getting mail while preserving your privacy; never having to update your address w/ everyone when you move (just w/ the USPS); cheaper & easier than PO boxes.
Take a look & tell them (and me) what you think. :-)
"You see, the internet is a series of tubes". Make the mail more like the tubes.
However, the way I proposed it, individual mail forwarding wouldn't cost you anything; the shipper just pays the average cost to send to a PAF address.
FWIW, if you do like it and want it to happen — or if you have suggestions for improvement — please tell that to the PRC directly! See http://s.ai/paf/#formal for instructions.