In 1976 I was in kindergarten, and like any five-year-old looked forward to the high point of each day: the arrival of our latest ditto-ed handout. For those of you under 30, let me explain that a ditto (similar to a mimeo) was a purple-inked paper used to mass-produce in-class exercises, and in the over-12 set, used for church newsletters and other low-circulation, low-budget publications. As soon as the dittos were handed out, we held them up to our faces and inhaled deeply: the smell of happiness, and as it turns out, methanol.

You over-30s, take note of the fact that I had to explain this item from our collective archive. Over the past few years I’ve had a few thirtysomethings stare at me blankly when I made a passing reference to dittos. When I started school, the ditto and its ancestors had been captivating children for a full century: in fact, the mimeograph was invented by none other than Thomas Edison in 1876. But just ten years after I inhaled my first ditto in kindergarten, the ditto was more or less extinct (at least in North America), overtaken by the photocopier and the computer printer. Today’s 28-year-old American has never enjoyed the intoxicating high of methanol in the morning.

No, I'm not this old. But talking with a 25-year-old about dittos sure makes me feel like it. (Photo from the Navy Historical Center.)

The lowly classroom handout is like a radar gun for the speed of change. I’m not even 40 (yet), and I can play a very respectable game of “when I was a boy….” OK, so sniffing mimeos isn’t quite as dramatic as walking three miles to school through the proverbial snowdrifts. But when my mother was 39, there were only three everyday technologies that had become obsolete in her lifetime: passenger ships, telegrams and pantyhose.

As a 39-year-old in 2011, I can rattle off a list of obsolete technologies as long as my arm (partly thanks to the good folks at PC World). Faxes, floppy disks, polaroids, rotary phones, records, answering machines, cassette tapes, typewriters, camera film, the Sony Walkman.

Or more recently: Mosaic, usenet, magnolia, Friendster, Pets.com, Napster, geoCities, Flooz, SixDegrees, Digg, eToys, MySpace, the WELL, Google Wave. Sure, some of them are still around, but even they are ghosts of their former selves.

Our lives online have accelerated the pace of obsolescence because the next thing is now only a click away. And I’m the first person to to click, to look around the corner, to crane my neck for whatever’s new. The privilege of living in an era in which a century-old technology can be replaced in a decade, and a ten-year-old technology replaced in a year, is that we get to delight in a constant stream of novelty.

And we get to enjoy our lost technologies too. I can still remember the silky-slick texture of a fax curling between my fingers, the scrape of a needle across a scratched record, the thud of my Walkman as it rattled against my waist. Ask anyone who’s even roughly my age to talk about polaroids or rotary phones or mix tapes and you will hear memories of waiting for the picture to appear (huddled around the snapshot), memories of the clicking that the phone made (as the dial spun back to its home position), memories of listening to that first collection of Bruce Springsteen B-sides (in the car with the window rolled down so you could sing along). They’re visceral memories, made up of our physical interactions with these long-gone objects and the people with whom we shared them.

It’s harder to summon nostalgia for the treasures we’ve lost online. First of all, they’re never gone: they’re as close as a Google search, or if that fails, the Internet archive.And second, they were never here in the first place: they were always out there somewhere in the digital ether, visible only through the window of our computer screen. They’re hard to conjure up because we never formed those sensory memories. All I can recall of geocities is some bad html and a sense of persistent annoyance.

As we spend more and more of our lives online we will experience a faster and faster pace of change, yet fewer and fewer delightful memories of technologies past. We’ll have the challenges of continual reinvention without the pleasures of retrospection. We’ll have the opportunity to connect online through the latest social network, but lose the opportunity to connect offline through common reminiscences. Even though we’re 8 years apart, my husband and I can trade recollections of typewriters, floppy disks and dittos. A 20-year-old has grown up in a completely different world from a 28-year-old.

Without our visceral memories to connect us later we need visceral experiences to connect us now. My colleague Nancy White introduced me to the idea of listening to a common piece of music at the beginning of a text chat session: it puts all the participants in the same mental space. You can open two bottles of the same wine, one in each city, while you Skype with a friend. We may even be able to tie our digital experiences to that most powerful of memory-triggers, scent.

Anchoring our online experiences in our offline physicality will do more than enhance our online interactions, of course. Every step we take to create a more tangible online connection is one that makes it more memorable, too. And we’ll know we’ve succeeded if we use our future networks to reminisce about Facebook the way we use Facebook to remember the smell of dittos.