It was on 26 June 1974 that the first bar-coded retail product was passed over a supermarket scanner in the United States (a packet of Wrigley's chewie, no less). Since then the bar-code has come to dominate retail trade, with the vast majority of goods sold in advanced nations such as Australia, priced only by their bar codes.
But the ubiquitous blocks of black stripes aren't the most important part of it. They merely provide an unambiguous way for the information they represent to be communicated to the stores' scanners. That information is the Universal Product Code. The number is printed underneath the bar code on all products -- 13 digits that uniquely identify every single product. Each colour of each brand of reels of cotton has its own number. The 13 digits mean that there are enough numbers to go around.
Some estimates put savings through the introduction of the UPC/barcode at $US17 billion annually in the US alone, thanks to reduced labour costs (no more pricing every item and keying in the prices at the checkout), and improved stock control (much ordering is automated now, with computerised checkouts communicating with ordering systems).
But there are limitations with this system. For one thing, as you will have experienced at any supermarket, scanning isn't always reliable. And, for another thing, the bar code has to be actually presented to the scanner. It doesn't work at a distance.
So the next revolution is RFID, or Radio Frequency Identification. Imagine that the bar code is invisible, yet can be detected from some distance away.
It works thanks to the glories of the microchip. The device is simply a tiny piece of computer memory attached to a radio receiver and a radio transmitter. When it comes within range of an RFID-seeking radio signal, it simply transmits the unique number stored in its memory. Best of all, it doesn't even need batteries because the received signal is sufficient to power the transmitter circuit.
The details of the number and the protocols for operation are currently being finalised, but we already know several things about the RFID tags. First, their tiny memories are sufficient to provide a huge number of unique identifiers. It seems likely that a 96 bit numbering scheme will be used. That provides two raised to the 96th power different numbers. In our more familiar decimal numbering system, that makes for a 29 digit number! That's more than enough to individually number each square millimetre of the face of one hundred million planets the size of Earth.
Now you may think of things like the anti-theft tags already attached to clothing in some stores. But already RFID tags have been reduced to gain-of-sand-like sizes, and we can expect them to get smaller still.
And cheaper. They are presently in the several cents each pricing range, but one thing we know for certain about technology is that it just gets cheaper.
So let's fast forward a few years. You pile your groceries into a trolley and walk right out the door to the car. No lining up. No delays. The scanner on the exit simply reads all the RFID tags from the grocery items. And your identity from the RFID tag on your credit card. You would have previously lodged authorisation with the shop to draw funds from your account. The trolley, meantime, also has an RFID tag so the store can implement whatever trolley-return policy it thinks wise.
In addition to taking money from your account for your purchases, the sales system continuously updates the purchasing system to make sure the shelves are stocked. Stock-takes are eliminated, because the shelves themselves track their contents. Shelf contents and sales can be continuously reconciled.
Of course, the idea of microscopic tags, purchase tracking and such things cause alarm bells to ring amongst privacy advocates. How about RFIDs imbedded in your clothes, allowing your movements to be tracked? Already various politicians in the US are trying to regulate RFIDs.
Fortunately, the RFID and retail industries are responding with their own operational systems. So before RFID tags start appearing on individual products, you can expect that the checkout scanners will do one other thing after they read the item's identifier: they'll issue a 32-bit 'kill code' that causes the tag to permanently switch itself off.