LETTERBOX: Letterbox hybrid caches are just like traditional caches, except they include a stamp with the log book. Locate the cache as you normally do; use your own stamp (if you have one) to stamp the log book; and use the letterbox stamp in the cache container to stamp your own log book (if you have one). If you don’t have a letterbox stamp, feel free to just sign the log book as you would normally do in a traditional cache. Please leave the stamp in the container - it is not SWAG. Thanks.
Before the time of radio, telephone, or TV, the only connection to the rest of the world was through newspapers and the mail. For those that lived in rural areas, they may not see a newspaper or travel (sometimes many miles) to the nearest post office but on occassion - or pay somebody to deliver mail to them. In 1896, the Post Office Department established rural free delivery (RFD).
Rural free delivery took years to implement and with it, RFD removed the isolation of America's rural residents. At the time rural free delivery began, it was as big an impact for communication as the internet one hundred years later.