Tiny radio tags that track our purchases could be commonplace on supermarket items within the next decade - a time-saver with serious privacy implications.
DOT.LIFE - how tech changes life, every Monday
By Alfred Hermida
BBC News Online technology editor
We are all familiar with the hassle of unpacking a supermarket trolley at the cash till. But in a few years' time, shoppers could be able to simply walk past a check-out which will automatically recognise the goods and debit your account.
This is how we shop today...
While this may sound like science fiction, the technology to do this already exists. It is known by the acronym RFID, which stands for radio frequency identification.
It works much like a barcode, but instead of having to be passed in front of a scanner, tiny transponders send out radio signals. Each tag is unique so any one item, be it a pack of razor blades or a shirt, can be tracked individually, all the time and just about anywhere.
Some experts predict this technology will become commonplace over the next decade or so. At present, it is too expensive to put on individual products and instead big companies use it to track shipping pallets. But as with everything in the tech world, the trend is towards smaller and cheaper devices.
"RFID technology is still too expensive," says Christian Koch, of the software company SAP, which is involved in trials of the technology at a German supermarket. "But it will come. It is only a question of when and how fast."
This sort of talk has alarmed civil rights groups, concerned about the implications for privacy. Does it mean people could be tracked by tags in their clothing, for example?
The companies involved admit that privacy is a tricky area.
... but is this the future?
"We have to present the technology in a way that attracts the consumers," says Mr Koch. "If the consumer doesn't accept the technology, it will never get into the store."
"As a consumer, you are interested in getting the right product at the right time at the right price. This is what the consumer wants and RFID can help companies do this."
For a business like a supermarket chain, the attraction of tagging is obvious as it allows the company to keep tabs on stocks, on the goods on shelves and to track stolen goods.
So far RFID trials have met resistance and suspicion. In the US, retail giant Wal-Mart has abandoned plans to put tags on razor blades because of consumer protests.
And a tagging system at Prada in New York has ruffled the feathers of its shoppers, who did not want the size of the clothes they were trying on being beamed into the air.
But RFID makes sense for big companies. This month, Marks and Spencer has become one of the first retailers to test individual tags on men's shirts, ties and jackets in one of its London stores.
Widespread tagging would allow a large retailer like M&S to know the exact location of any of the 350 million garments it sells a year and help staff find a different size quickly.
Question of trust
For people like Glover Ferguson, the chief scientist at consultants Accenture, RFID technology means we need to think again about the norm of what is privacy.
"The question is, do you trust who you are giving the information to?"
"We will be more willing to surrender privacy if we get something in exchange and are aware of the risks of giving that information," he says, pointing to popularity of supermarket loyalty cards. These allow stores to build up a detailed profile of each customer's shopping habits, in exchange for discounts or cash vouchers.
"It is a question of perception. RFID could be presented as a service by a store where you regularly shop," says Mr Ferguson.
Beyond the supermarket, the potential uses of smart tags are enormous. Washing machines could be able to identify clothes and choose the appropriate cleaning cycle.
Or a car could come with sensors that track wear and tear, sending the information back to the mechanic, and alerting the driver of any potential problems.
Mr Ferguson predicts that widespread tagging will become a reality by 2010, despite privacy qualms.
"It is like nuclear energy, you can't uninvent it. We're going to have to learn to live with it. The genie is out of the bottle."