In the USA zip-codes are so central to your identity that it's hard to credit that they haven't always been there. But ZIP [Zone Improvement Plan] codes were only implemented in 1963 to allow the development of machine-driven mail-sorting. The 5 digit ZIP code only gets you to your city-district or town. In 1983, the USPS introduced a ZIP+4 or the form 01534-1819 which would zero each letter to a city block. The great American public folded their arms dug in their heels and refused to adopt that new fangled nonsense and ZIP+4 quietly drifted off into the back-waters of history. But technology superseded the wooden-headed intransigence of Sam Public. The vast majority of mail is typed or printed and optical character readers OCR were developed that could reliably read 98% of al envelopes and spray a series of machine readable dots on the paper that would drive the letter through a sorting machine to State - City - District - Post-round - "delivery-point". In general the ZIP codes go East to West with 0xxx numbers in New England and 9xxx numbers in Alaska.
The Brits followed suit and by 1972, almost all UK addresses had a "Post-code" of the form CM5 0PL, where the first section is sort of mnemonic for the post-town, here Chelmsford, Essex, with digits 0-9 added as the addresses float off towards the periphery, the second section, like the [ZIP]+4 is more arbitrary. I remember going to the post-office in Chelmsford with my sister in ?1971? and using a machine that revealed our post-code and printed a sheet of return-address stickers: but that might be a retro-spective fantasy. I do know that I wrote a letter addressed to "Bob T. Scientist / CM5 0PL" and it was successfully delivered: our family shared that rural post-code with one other house. That was in the nature of a scientific experiment. When I was much younger, my naval father was stationed for a year in Singapore and I wrote him a letter addressed to "Commodore H.L. Scientist / Singapore". That also arrived eventually but counter-stamped with numerous not-known-here annotations as it went the rounds of fortress Singapore. The UK Post Office still requires a tedious level of redundancy in written addresses to "ensure delivery", not only the post-code, and the post-town but also the County. It's like they don't have the courage of their technological convictions.
A certain cohort of the British population only had to deal with people who had a three line address, such as "Sir Joseph Plutocrat / Dotheproles Hall / Norfolk". As a teen, I had a thing about the great-grand-daughter of John "Nobel" Strutt; one of her grandparents always addressed letters to a friend, who lived in Godalming, as "Stephen Palomino / Godalming Castle / Suffolk" because he 'didn't know' anyone who lived in Surrey: a stew filled with riff-raff, cads, counter-jumpers and stock-brokers. Whatever about British postmen, as a small third-world country where postmen knew and/or were related to everyone they delivered to, Ireland was slow to adopt post-codes. So much so, that by the early 1990s, when the volume seemed to indicate a need for such a system, the OCR technology had really improved to a high-level of reliability. The management of An Post decided that they could by-pass post-codes and just OCR read and electronically code the addresses. An urban legend circulated at the time that all the letters for Canada Life Assurance were filtered off into an enormous sack and shipped to Toronto. It is 20 years since that 'solution'.
EirCode, a company charged with matching every home and/or 'delivery-point' with a unique identifier. You can search for your own code or those of your pals. Either by typing in the address or zoom-and-swooping over a digital map of the country. It's like a Sink-the-Lusitania video game: you move the sights until they coincide with the red dot in your house-of-choice and click. This is less useful for regular An Post mail because, as I say, Irish postmen really know their patch and deliver something to almost all their households at least once a week. But for all the other delivery people who have a huge and sparsely populated area to cover, Eircodes are a godsend. I had something delivered by DHL last month. Their deliver-driver operated out of a shed near Dublin airport and covered three counties every day. It was too complex to give him directions over the telephone so I said "Can you deliver it rather to The Institute" and we both heaved a sigh of relief when he said Yes. In 2012, when I was 'resting' or 'working from home' for most of the week, I handled a few courier deliveries by diverting them to O'Shea's of Borris where we buy occasional pints of milk and beer. One time that didn't work out so well because the driver had been through Borris already and didn't want to back track, so I airily said I'd meet him "at the cross" below our house. I trotted down the lane and along the county road wondering who had sent us a book. It turned out to a a case of wine [generous friends in the run up to Xmas] which I had to schlepp back up the hill with increasingly lloonngg arms.
Eircode apparently cost €27,000,000 to bring to market, for a unique number for 2.2 locations. At the moment 35% of Irish addresses, including ours, are shared with other people. This is a problem for deliveries but also for emergency services. Sounds like a lot of sugar for a bit of programming and cross-referencing of existing databases, but it's buttons compared to Irish Water spending €86m on "Consultants". The lead 'directional' part of the the seven-figure eircode is information rich: all Dublin addresses use the existing postal districts: D1 becomes D01, Cork addresses all begin with T; Kilkenny is R95, Carlow is R93 etc. Not in anyway mnemonic like the UK post-codes, though, more like ZIP codes. Geek-interestingly, the 4digit trailing-end of the code is deliberately not sequential, the randomness of these figures serves as a internal consistency 'checksum'. There are all sorts of reasons why non-sequential, non-hierarchical numbers are a bad idea, and the coding is not 'open-source' but rather proprietal information that the company intends to sell to recoup its investment. So complementary development of Apps using geographical location will be hard to implement. And this investment of tax-payers money only handles one sort of location - home. If you have an accident while out and have to call emergency services then Eircode won't help. My car broke down in Dublin a couple of weeks ago and I called AA rescue services. Had to ask two girls sitting on a wall what the street was called. If I'd broken down on an Irish back-road, I don't know how I would have called the AA's yellow van to my side; particularly if I was off my regular commute-route. Roll on the time when we have SatNav chips embedded in our shoulders. More sensible alternatives.
Anyway lets by-pass Postcrossing, which is 10 years old this week. If you send a letter to "Bob the Scientist / R95 R6X6 / Ireland" we'll see how good the system is.