In the Spring of 2006, a trainee teacher and single mum called Stacy Snyder was summoned by Millersville University in Pennsylvania and informed that, despite having passed all her coursework and earned all her credits, they were not going to award her a teaching qualification. She was, the letter informed her, guilty of “behaviour that was unbecoming of a teacher.” What kind of behaviour? Snyder, it turned out, had once posted an online photo of her in fancy dress and wearing a pirate’s hat. The university authorities, alerted by a snitch at the school were Stacy was training, argued that the picture might expose potential students to the trauma of seeing a teaching drinking alcohol. Snyder tried to fight the decision, but the damage had already been done. Even three years later, type “Stacy Snyder” into Google and the first hit which comes your way takes you straight to the same innocuous-looking photo.

Synder is not the only one to have her party photos still knocking around online. Cheap digital storage is tempting companies to back all their information up in huge digital vaults. The rest of us are following suit, “life caching” almost everything about ourselves online via Facebook and photo-sharing sites like Flickr; since young people tend to be more fluent and more trusting of online social networks, they are more likely to throw all their data into the machine. Now, however, a 43-year old Austrian academic based in Singapore is campaigning for a solution which might allow us to time-expire all our digital dealings. It first struck him a couple of years ago, says the former Harvard scholar Viktor Mayer-Schönberger, how much effort it used to take to remember stuff because forgetting was the default mode by which our memories naturally decayed over the passage of time. No longer. In putting all our stuff online or typing everything that goes through our head into the electronic ether, he says, we are quite unconsciously creating a “digital memory that vastly exceeds the capacity of our collective human mind.” This inability to forget in an age of digital storage might do irreparable harm to the time-honoured principle that everyone deserves a second chance, that everything about us should be scrubbed from the record after an appropriate lapse of time. “Ten years ago”, he told me, “people could look at gossipy stuff online about Michael Jackson’s dark secrets, but today we can go online and find things out about our friends and neighbours. It can really be quite revealing.” The ability to tag photos with people’s names on Flickr, for example, means that someone might use its search function to find a picture of you even if you’ve never used the site. Search engines like 123people.co.uk specialise in scavenging information about individuals from various places on the net and storing it all in one comprehensive database. Mayer-Schönberger, however, is no luddite. He doesn’t advise his students against using social networking sites and the net – they’d probably take no notice even if he did – but simply warns them that they material they’re uploading might later be used in very different contexts. Already, he points out, companies like ReputationDefender have sprung up to help individuals to wash away embarrassing details from blogs and online social networks, but that option only works for those who can afford it. “And if that’s the case”, Mayer-Schönberger says, “shouldn’t we equip a larger portion of the population to deal with more effective ways?”

Digital forgetting, of course, can have its uses. In 2001, for example, a 67 year-old computer engineer called Gordon Bell made the decision to record and store as much of his life as possible and upload it to his computer. By the time I came to interview him for my book, nearly seven years later, he had taken over one hundred thousand photos and had stored nearly one hundred and fifty thousand emails; in the same way that we all begin to forget telephone numbers because they are stored in the digital memory of our phone, Bell told me that he was starting to forget things about his life because he no longer needed to remember them. Mayer-Schönberger has spoken to Gordon Bell too, and acknowledges the advantages of delegating to computers to the leg-work of remembering everything. What Bell’s project didn’t allow for, he tells me, was what happens when our personal information is passed around. But even if that information could not be shared with others, he contends, it does us little good to have it hanging around on computers. His suggestion is that in the electronic age we need urgently to re-learn the art of forgetting. “For millennia, humans have remembered the most important elements of their lives and forgotten the rest. With digital technology, we have reversed the process. Today we remember everything and nothing is being forgotten. We have un-learned one of the most fundamental human traits.”

Mayer-Schönberger, however, has an audacious technical fix which might help us out. Suppose we could set any digital information we share or input with a date of expiry, he says, thus forcing our storage devices to undergo regular purges of our information. Users of a document, for example, wouldn’t be able to save their file without including an expiration date, thus reminding us to put forgetting back into our daily routines. At least in technical terms, says Mayer-Schönberger, such systems would be easy to put in place. Our digital cameras already record the time and the date at which their photos were taken, making them easy to wipe at a specified date. Upon entering a search query, too, users could be prompted to enter an expiration date, or could select one from one already set. The idea is not wholly fanciful. Some online start-ups like the New York file-sharing service drop.io already allow their customers to share information but with the proviso that the weblink should self-destruct after a prescribed period of time. Even some of the major internet players, says Mayer-Schönberger, realise through market research that people are concerned about all this, and are beginning to offer similar services like this because they want to remain competitive. The search engine Ask.com, for example, now offers searchers the option to erase their search query history. Even Google has followed suit; after 9 months, Google now voluntarily erases the identity of its searchers.

But surely Mayer-Schönberger’s technological fix ignores the fact that prurient companies and institutions are paying pay too much attention to unreliable information out there on the net. The reality, he replies, is there’s no way of knowing who’s been taking a sneaky peek at some of the gossip and innuendo about us online. “The fact is that these things are taken into account; an employer might say that they didn’t Google you, but they might have, he says, and there’s no way of proving it.” The most serious barrier in the way of his technological reminder to forget, he readily acknowledges, is our obsessive-compulsive need to hoard everything online. “We humans have been forgetting biologically for millennia, and that was an important part of ourselves, but now we need to adjust our desire to remember, and that means a painful process of adjustment. It’s a cultural problem more than a technical problem. It will be hard to achieve, but necessary.”