A couple of years ago, I was an operations analyst - my employer used USPS to deliver millions of DVDs... USPS completely depends on bulk shipping and they'll happily provide product packaging at all scales - down to the carrier route level. Urban areas get hit pretty bad, due to population density - bulk shippers get more bang for the buck. Ideally, from the postal customer's perspective, shipping costs would rise for shippers who can only address shipments to "Current resident of:" or "Our friend at:". Proof of work, like hashcash. But of course the incentive system is the direct opposite, the recipients are not the customer.