( CNN ) -- It 's the internet 's fault that , if the U.S . Postal Service has its way , you wo n't be getting letters delivered to your mailbox on Saturdays anymore . After all , how many stamps have you bought lately ? But the engine of the USPS 's demise could also save it . After all , how many packages have you received from Amazon lately ? And would n't you like to get them faster ? Postal Service spokesman John Friess says that while its letter-carrying business is shrinking , its package-delivery business is growing . ( Note that postal carriers will still be delivering packages on Saturdays . ) In its anxious search to make money any way possible , the agency late last year began testing a same-day delivery service in San Francisco for online purchases . While the experiment , called Metro Post , is starting out small , it also comes at a time when the world 's largest online retailer might be looking for a lot of trucks and a lot of drivers who can do same-day delivery cheap . Amazon 's strategy for consumer domination includes erecting million-square-foot warehouses near the country 's largest cities . The company has played coy on whether its expanding physical infrastructure signals plans to offer same-day delivery on a wide scale . If so , it will still need a transportation infrastructure to go along with it . And that fleet ca n't just consist of UPS trucks that Amazon tells to go faster . Same-day delivery requires a fundamentally different logistical framework from its standard system , logistics experts say . To get orders delivered even as quickly as overnight , Amazon pulls together the orders at its distribution centers before turning the packages over to UPS or FedEx . The carriers then feed those packages into their own logistics operations , which typically means traveling to UPS or FedEx distribution centers and depots before heading out on trucks to people 's houses . All of that transit does n't move fast enough for same-day . To make same-day work , the orders must travel straight from the distribution centers to customers . Of course , Amazon could hatch plans with UPS and FedEx to offer same-day . Unlike those two companies , however , which both have thriving businesses doing what they already do , the USPS has drivers with fewer letters to deliver and a desperate need to innovate . According to the optimistic logic of the so-called sharing economy , that seemingly dire scenario does n't look like a problem ; it looks like idle capacity just waiting to be leveraged . According to Friess , the Postal Service would n't need to hire new drivers or buy more trucks to offer same-day , Friess says . The agency would simply have to adjust where its drivers were going and when . `` We already have the existing infrastructure in place , '' he says . `` That 's what sets us apart . '' The postal service still has miles to go before becoming Amazon 's courier of choice . The pilot program is limited to delivering a maximum of 200 packages per day to customers of 1-800-Flowers.com 's sister brands , which sell popcorn , cookies , chocolate and gift baskets . Friess says the USPS is planning to add more retailers soon . If the test is successful , which he says the agency believes it will be , Metro Post will roll out to other large markets across the country . Friess declined to speculate on whether the USPS ' 214,000 trucks â€ ” what the agency calls the world 's largest civilian fleet â€ ” could end up in the service of Amazon . But he said he believed the USPS will start to look increasingly attractive to other companies exploring the same-day option : `` We 'd never close the door on ways to expand our revenue . '' Subscribe to WIRED magazine for less than $ 1 an issue and get a FREE GIFT ! Click here ! Copyright 2011 Wired.com .
Internet has hurt the postal service , but could also be its savior . Amazon could go to same-day shipping , and use U.S . Postal to do it . Comment: