The first airmail flight in Germany, 1912.
The postal system was important in the development of modern transportation. Railways carried railway post offices. During the 20th century, air mail became the transport of choice for inter-continental mail. Postmen started to utilize mail trucks. The handling of mail became increasingly automated.
The Internet came to change the conditions for physical mail. Email (and in recent years social networking sites) became a fierce competitor to physical mail systems, but online auctions and Internet shopping opened new business opportunities as people often get items bought online through the mail.
Modern mail is organized by national and privatized services, which are reciprocally interconnected by international regulations, organizations and international agreements. Paper letters and parcels can be sent to almost any country in the world relatively easily and cheaply. The Internet has made the process of sending letter-like messages nearly instantaneous, and in many cases and situations correspondents use electronic mail where previously they would have used letters. The volume of paper mail sent through the U.S. Postal Service has declined by more than 15% since its peak at 213 billion pieces per annum in 2006.
The worldwide postal system comprising the individual national postal systems of the world’s self-governing states is co-ordinated by the Universal Postal Union, which among other things sets international postage rates, defines standards for postage stamps and operates the system of International Reply Coupons.
In most countries a system of codes has been created (referred to as ZIP codes in the United States, postcodes in the United Kingdom and Australia, and postal codes in most other countries), in order to facilitate the automation of operations. This also includes placing additional marks on the address portion of the letter or mailed object, called “bar coding.” Bar coding of mail for delivery is usually expressed either by a series of vertical bars, usually called POSTNET coding, or a block of dots as a two-dimensional barcode. The “block of dots” method allows for the encoding of proof of payment of postage, exact routing for delivery, and other features.
An automated postal machine
The ordinary mail service was improved in the 20th century with the use of planes for a quicker delivery. The world’s first scheduled airmail post service took place in the United Kingdom between the London suburbs of Hendon and Windsor, Berkshire, on 9 September 1911. Some methods of airmail proved ineffective, however, including the United States Postal Service’s experiment with rocket mail.
Receipt services were made available in order to grant the sender a confirmation of effective delivery.
Worldwide, the most common method of prepaying postage is by buying an adhesive postage stamp to be applied to the envelope before mailing; a much less common method is to use a postage-prepaid envelope. Franking is a method of creating postage-prepaid envelopes under licence using a special machine. They are used by companies with large mail programs, such as banks and direct mail companies.
In 1998, the U.S. Postal Service authorised the first tests of a secure system of sending digital franks via the Internet to be printed out on a PC printer, obviating the necessity to license a dedicated franking machine and allowing companies with smaller mail programs to make use of the option; this was later expanded to test the use of personalised postage. The service provided by the U.S. Postal Service in 2003 allows the franks to be printed out on special adhesive-backed labels.
In 2004 the Royal Mail in the United Kingdom introduced its SmartStamp Internet-based system, allowing printing on ordinary adhesive labels or envelopes. Similar systems are being considered by postal administrations around the world.
When the pre-paid envelope or package is accepted into the mail by an agent of the postal service, the agent usually indicates by means of a cancellation that it is no longer valid for pre-payment of postage. The exceptions are when the agent forgets or neglects to cancel the mailpiece, for stamps that are pre-cancelled and thus do not require cancellation and for, in most cases, metered mail. (The “personalised stamps” authorized by the USPS and manufactured by Zazzle and other companies are in fact a form of meter label and thus do not need to be cancelled.)
Privacy and censorship
“The Steamboat” – mobile steaming equipment used by Czech StB for unsticking of envelopes during correspondence surveillance
Documents should generally not be read by anyone other than the addressee; for example, in the United States of America it is a violation of federal law for anyone other than the addressee and the government to open mail. There are exceptions however: executives often assign secretaries or assistants the task of handling their mail; and postcards do not require opening and can be read by anyone. For mail contained within an envelope, there are legal provisions in some jurisdictions allowing the recording of identities of sender and recipient.
The privacy of correspondence is guaranteed by the constitutions of Mexico, Colombia and Brazil, and is alluded to in the European Convention on Human Rights and the Universal Declaration of Human Rights. The control of the contents inside private citizens’ mail is censorship and concerns social, political, and legal aspects of civil rights. International mail and packages are subject to customs control, with the mail and packages are often surveyed and their contents sometimes are edited out (or even in).
There have been cases over the millennia of governments opening and copying or photographing the contents of private mail. Subject to the laws in the relevant jurisdiction, correspondence may be openly or covertly opened, or the contents determined via some other method, by the police or other authorities in some cases relating to a suspected criminal conspiracy, although black chambers (largely in the past, though there is apparently some continuance of their use today) opened and open letters extralegally.
The mail service may be allowed to open the mail if neither addressee nor sender can be located, in order to attempt to locate either. Mail service may also open the mail to inspect if it contains materials that are hazardous to transport or violates local laws.
While in most cases mail censorship is exceptional, military mail to and from soldiers on active deployment is often subject to surveillance. In active fighting, censorship may be especially strict to hide tactical secrets, prevent low morale from bad news, etc.
Rise of electronic correspondence