(((It's very clear that the postal system is not a dead medium. However, the physical and economic structure of the posts has undergone profound, elaborate changes over the centuries. Early postal systems often doubled as espionage networks, and were often proverbially corrupt.
(((Before the introduction of the flat-rate penny post in Britain, prices were high, yet geographically and socially inconsistent. Posts were also riddled with off-the-books "franking" privileges exercised by various privileged classes of users. Recipients were billed for posting through a 'collect on delivery' practice. These structural weaknesses in the postal system created a booming underground in black-market mail-fraud. Alvin F. Harlow's avuncular and chatty history takes a deep prurient interest in these illicit goings-on.)))
"There were scores of devices for the sending of a few elementary facts by mail without paying for their carriage. One of the commonest media was the newspaper, which at that time the post carried free of charge. (...) A line drawn under the name of a Whig politician meant that the sender was well; under a Tory meant 'not so well.' There were other signals which told other things. Apparent instructions to the post written on the wrapper were secret messages. Among those which the Post Office detected and for which it assessed fines were, 'With Speed,' 'Send soon,' 'To be punctually forwarded,' 'With my compliments,' 'Postman, be you honest and true,' 'It is requested that this letter be delivered without delay, otherwise a complaint will be made to headquarters;' all of which meant something entirely different.
"Business men had code systems based on the writing of the address. One man's address might be varied thus:
William Henry Perkins, 97 Pump Court, London
William Henry Perkins, Pump Court, London
Wm. Henry Perkins, 97 Pump Court, London
Wm. Henry Perkins, Pump Court, London
William H. Perkins, 97 Pump Court, London
William H. Perkins, Pump Court, London
W. Henry Perkins, 97 Pump Court, London
W. Henry Perkins, Pump Court, London
Will H. Perkins, Wm. H. Perkins, W. H. Perkins, William Perkins and so on were other variants; then a change could be made by putting Mr. before each of the names, or adding Esq. after them. Mr Perkins' address could be differently stated: 'At the sign of the Golden Dog,' or 'Opposite St. Somebody-or-Other's Church.' Actually hundreds of changes might be made, all of which were recorded in a key book and each one having its meaning; the state of the market, bids, quotations, orders, cancellations, notice of arrival and transmission, etc.
"The manner of using the collect-on-delivery postage system for the free transmission of news is illustrated by an anecdote told by the poet Coleridge. While travelling in the north of England he halted at a wayside inn just as a postman was offering a letter to the barmaid. The postage was a shilling. Sighing sadly, the girl handed back the letter, saying that she was too poor to pay it. Coleridge, over the girl's objection, insisted upon paying the shilling. When the postman was gone, she opened the letter and showed the poet that it was only a sheet of blank paper; but there were a few hieroglyphics on the back of it, alongside the address, which she had glanced at while she held the letter and which told her the news. 'We are so poor,' the girl explained, 'that we have been forced to invent this method of franking our letters.'
"Franks were the curse of the mail service then, not only in England, but in America and other countries as well. One twelfth of the letters sent from London went free. Members of Parliament and government officials by the hundred were authorized to frank letters, and few of them were averse to handing out whole batches of letter paper with their names written thereon to friends and constituents. By one clever scheme of the evaders of postage, a frank was made as elastic as a rubber band. Three or four friends or associates in as many cities would agree to use the name of one of them in their correspondence. *A* at London would then send a letter to *B* at Dublin, having the cover wafered and sealed so that it could be opened without breaking the seals. *B* would write a letter, enclose it in the same wrapper (...) and without changing the name would mark out his own address and write *C*'s address in Edinburgh, as if *B* had removed to that place. *C* would receive the letter, alleging that *B* was visiting him, write another letter and enclose it to *D* at York. Thus one frank would carry at least three or four letters before it became so covered with addresses as to arouse suspicion."