Ad banner cookies—On behalf of the USPS, persistent cookies and beacons (described below) may be set and managed by third party advertising suppliers to support ad banners. Ad banner cookies are set when you view or click on an ad banner on usps.com, or an ad banner on another site for a USPS product, and persist for no more than five years.</p> </li> </ul> Web Beacons <p>A Web beacon, also referred to as a clear gif or page tag, consists of code on the USPS site that delivers a small graphic image from another Web site or third party server.