In the era of the 140-character Twitter post, what’s to become of that classic travel memento, the postcard?

A postcard is a tweet with a stamp. I reached this conclusion recently, after becoming perhaps the last person in North America to board the social media–networking bandwagon. I signed up for Twitter and tweeted for a minute. I joined Facebook and watched my friend cohort expand. I write the word friend without the sneer of inverted commas (“friend”) because I feel there is something inherently optimistic in the notion that the Web ether is crowded with people one knows or may wish to, if only it were easier to be in touch. But the truth is, I don’t like communicating through social-media networks, if indeed communication is the point. It may mark me as old-fashioned, but I hold out for archaisms like phone calls and face time and the handwritten note. And a postcard is to a proper letter as a tweet is to an e-mail. It is the jotted notion, the short form, a shout-out with few strings attached.

My own postcard habit started early, probably around the time my mercurial father announced at the breakfast table a plan to move the family from New York to L.A. That this ambition was not anchored in anything like reality (we knew no one there; he had no set job prospects) was little deterrent to him or, for that matter, to the eight-year-old I was.

We never made it to California, of course. Not understanding as I later would the fickle ways of the parental mind, I immediately began planning our trip. I wrote away for maps and brochures. I ordered trip planners that, when they arrived by mail, often came with a postcard. I still have one of those cards, a matte polychrome rectangle ornamented with graphics that predate the era of the politically correct. The card offers Greetings from Utah. Fat stripes adorn the bold, stolid letters of the state name—the ample bucket of U, the upright T, the tepee of A, the H like a big, handsome gate—and serve as a foundation for images of a salt shaker, a bag of copper, a goofy Native American with a feathered headdress, and a beehive with a thought bubble enclosing this weird invitation: C’mon get it. Get what? Encoded on the card’s face is a key to the civic attractions of a state that, in those days, could boast of more sheep than people and whose big tourist draws were the spooky Canyonlands and the Bonneville Salt Flats. Conspicuously, there are no Mormons at all.

That particular card is of a type that originated in what aficionados term a golden age in postcard history, a time when the front of a card contained a single image and the back was reserved for text. (Card faces were left blank in the earliest versions.) But what made it wonderful to me then, and still does, is the block of statistical information it contains. “Copper, lead, and silver are mined” in Utah, it informs the reader. “The sego lily is Utah’s state flower.” These random fragments joined by ellipses read to me as found poetry. They somehow evoke a state I had never set foot in until recently. They conjure up the place in a manner that technology has rendered obsolete. There’s an app for that kind of data nowadays.

Yet somehow, the more that apps reduce the world to cunningly manageable integers of data, the more appealing the old forms of communication become. The staggering volume of postcards one sees on eBay and in flea markets and in every gift shop on the planet provides a clear sense of how common the urge once was and how durable it remains.

I send postcards whenever I travel. I hunt down vintage black-and-white views in the grotty flea market at the Porte de Vanves, in Paris; garish 60’s girly cards that seem to be a specialty in Berlin; hokey Dutch cards depicting wooden shoes or windmills or wheels of Gouda. I pick up unusual cards in unexpected places, like the fish-eye panoramas sold at the Basilica di San Marco, in Milan, of a little monastery where Mozart hung his hat for two months in 1770; or the print of a particular dreadlocked holy man in Varanasi, India, who is such a relentless camera hound that his image is probably stuck to dorm-room corkboards and refrigerators around the world.

Postcards seem particular to locale in the way that Slow Food is. Not incidentally, they are also slow. It takes effort to find and buy and write and stamp and mail one, and in that time a kind of alchemy occurs. The world is rescued from those who would shrink it to pocket size, to a snap on a Wall, and restored as a place of vastness, mystery, and an illimitable supply of bad visual puns.

Historians of Facebook and Twitter will be left to scrounge around the Internet for the fugitive relics of the present communication age. Not for them the scene upon scene of assorted wonders (the Golden Gate; Moroccan dancing boys; the Alps, as seen from Interlaken; Mount Fuji; the Andes; Titian’s Venus; two mandrills from the Cincinnati Zoo) preserved in the poet James Merrill’s postcard box. “Cards from all over,” Merrill wrote in a little-known poem titled “The Friend of the Fourth Decade.” “God! Those were the years.”

Merrill never threw a card away and neither do I. What my pals choose to do with the cards I send is no business of mine. If they preserve them, it cannot be because of anything profound in the messages, which are limited to the commonplace. I record the weather, mention the sights, and remember to note the price of things, as the diarist Samuel Pepys did.

I could do all of that in a tweet, of course, or on Facebook, or on an e-card sent from my phone. But then that would deprive my actual friends of the pleasure of coming across a souvenir in the mailbox, some goofy hula maiden or cheesy sunset scene, wedged among the Valu-Paks and unwelcome bills. It would also deprive me of a ritual increasingly important to me when I travel, an act of summoning up those I care for and closing the distance between us with that banal yet sincere declaration: “Wish you were here.”

Guy Trebay mailed his last postcard from Paris.