The U.S. Postal Service is the only delivery service that reaches every address in the nation: millions of residences, businesses and Post Office Boxes. The Postal Service receives no tax dollars for operating expenses and relies on the sale of postage, products and services to fund its operations. With retail locations and one of the most frequently visited websites in the federal government, usps.com, the Postal Service has annual operating revenue of billions and delivers lots of the world’s mail. They are one of the nation’s largest employers. And they have one of the world’s largest computer networks.