The cellphone grows more wondrous and indispensable to us every day. Talking is the least of it. We text and Tweet our heads off, send photos, watch TV shows, play video games. But in Japan, imperium of the future where all the above is old hat, the keitai (cellphone) has further spawned a wildly successful, populist fiction genre. Keitai shosetsu, the so-called cellphone novel, has been touted (in the pages of the New Yorker, among other places) and reviled (by Japanese literati) as the first narrative mode of the txt msg age — the herald of a written-word future bent by wireless telecom’s powers.

I’m the first and only American author who’s written for Japanese cellphones (and with literary intentions at that). A happy lesson in old-fashioned technique, it was a sobering one about our brave new cyber-world’s eternal essential: interactivity. Most of the auteurs of keitai shosetsu are Japan’s vast demographic of girls and 20-something young women, who thumb out ultra-lurid, mawkish teen romances on their cellphone keypads in scraps of manga-like dialogue, skimpy action, texting slang and emoji (emoticons). They post these skeletal pseudo-confessions in installments, under cute pseudonyms, on dedicated Web sites like Magic i-land and Wild Strawberry where they can be read for a low fee.

Astronomically popular (chiefly among millions of Japanese teen girls), “thumb novels” are much decried as trash for yahori (slow learners, i.e., half-literates). And over recent years this subculture has stormed Japanese commercial book publishing. In 2007 — keitai shosetsu’s annus mirabilis –half the top 10 fiction bestsellers in the shrinking Japanese book market originated on cellphones. Overall list-topper “Love Sky,” by the self-styled “Mika,” has sold 2. 9 million copies in tandem with its sequel, which ranked third.

Last fall a literary grandee joined in. Jakucho Setouchi, the Marguerite Duras of Japan, revealed herself as “Purple,” author of a keitai shosetsu, “Tomorrow’s Rainbow,” about a teen’s search for love after her parents’ traumatizing divorce. Delightfully, Setouchi is also a celebrated 86-year-old Buddhist nun who wrote a contemporary update of “The Tales of Genji,” Japan’s racy ur-novel classic.

But before the great Setouchi stooped to keitai, I beat her to it. In late 2002 I was in Tokyo my first time. Unlike Bill Murray in the Sofia Coppola movie, I’d found myself in translation. Three of my books of brief quirky tales had been very happily serialized and published in Japan. It’s still where I sell most. One morning I watched a Tokyo teen Web-browsing on his cellphone. I was amazed. I’d never yet heard of i-mode, the vanguard keitai Internet service launched in 1999 by Japan’s telecom giant NTT DoCoMo. I’d never even owned a cellphone. But I’d been on MTV with my surreal mini-fables; I’d adapted them into a very episodic indie film that still lives a happy second life online. My work, I always felt, fit the short-attention-span age to a T.

Here at last, it seemed, the culture was catching up with my literary brevity. Despite the impact of Raymond Carver (god of MFA writing programs, and of me too), the short story in general got short shrift in fiction’s limelight. And ultra-shorts were practically offstage. But now technology was about to fix the script.

My translator, professor Motoyuki Shibata of Tokyo University, Japan’s foremost translator of contemporary American writing, enthusiastically agreed. (He didn’t own a cellphone either.) So back in New York I hatched a format: no story over 350 words, for minimal thumb-scrolling; 12 words tops for opening sentences, to fit whole on a single screen.

“Make it shorter,” says Woody Allen, citing all-purpose comedy-writing advice. I got into shortness originally to fight an awful tendency to bloviate. And over the years, I’ve sometimes gotten identified with genres like “sudden fiction” and “flash fiction.” But I call what I write simply “stories.” Compression, I find, intensifies everything. The reader’s imagination will hungrily conjure from the bits you shrewdly serve. Or withhold.

I began my keitai shosetsu in late 2003 (shosetsu means “fiction,” in fact, not “novel”). I knew nothing of “Deep Love,” the seminal Japanese cellphone novel about a sex-for-money girl teen, which had just become the first of its kind to be brought out by a book publisher. (Written by “Yoshi,” actually a 30-something guy, it’s sold almost 3,000,000 copies.) I wrote, as usual, in longhand, reworking on laptop. Here purists might squawk. Even ancient Jakucho Setouchi began “Tomorrow’s Rainbow” on her cellphone — but soon gave up and switched to her customary fountain pen, writing vertically on paper.

Prostitution, AIDS, rape, incest, abortion, drugs, suicide, desperate eternal love: These are the stock in trade of keitai shosetsu’s world. I was clueless. I did figure on youngish readers (of both genders), and the need to Japanify. Shame, I did know, was big in Japanese culture. It was big with me too. So I riffed away, repeatedly, opening with a three-fer about a young office worker, mortified to have accidentally swallowed his cellphone.

Of course I invoked manga, karaoke, baseball (a headless batter) and J-pop. Then I went searching for gold online, at sites like Trends in Japan. My translator marveled at my cultural savvy as I sent up young depressed male shut-ins (hikikomori), needy geeks (otaku), the Burberry fashion craze and the monstrous hegemony of Cute (kawaii). To be plain saucy, I recycled an old item of mine about a horny guy and a cynical sheep.

My pioneering literary keitai shosetsu finally launched with three mini-tales a week, downloadable for a low fee from the “cellphone paperback” i-mode site of my book publisher Shinchosha — 78 stories all told. When they later came out as a slim regular hardback called “I-Mode Stories,” 100,000 readers had accessed them online, which seemed like a pretty fine number. Until I later learned of the 3.25 million racked up by literary nun Setouchi. Revisiting Tokyo in 2007 I’d be recognized on the street; but “I-Mode Stories” sold very modestly, no match even for my other, conventional books.

I know now what probably cost me most: lack of interactivity. I wrote my Kafkaesque whimsies the old, author-as-impervious-god way. I treated the cellphone screen as an innovatively accessed, but inert, mini-page. Keitai shosetsu, however, exist in vast online pools, where writers and readers can dynamically engage with each other. And that’s key. Yoshi shaped “Deep Sky” based on ongoing hits and e-mails. (He even handed out fliers.) Keitai readers notoriously aren’t big book buyers — but they will buy books as mementos of their communal involvement.

Despite warming U.S. press coverage, so far the keitai shosetsu phenomenon hasn’t crossed over here. Yes, a couple of new Web sites, including one from a Japanese company, DeNA, now offer “cellphone novel” templates. But cellphones play a crucially different role in Japan. They, not computers, are the principal portal to the Internet. “The majority of my students (19-22-year-olds) don’t have a P.C. e-mail address,” notes Yuki Watanabe, a Ph.D. candidate in American lit in Tokyo. “Many don’t have a P.C. at home.” They’re of the keypad, not keyboard, generation. The lingo of texting is normal language to them, and they’re tuned to its subtleties.

Just as influentially, says my friend Roland Kelts, cultural critic and author of “JapanAmerica,” Japanese daily commutes often last two hours each way. “Holding a cellphone screen inches from your face on a packed commuter train and reading a confessional, melodramatic narrative” provides the perfect intimate package of content, technology and portability. Keitai shosetsu’s mainstream success, though, is taming its edgy subculture content, according to one Japanese observer. And professional writers are now being hired to supply “amateur” cellphone narratives.

For the U.S. and U.K., the venue where words and cellular/cyber technology seem to be feeling for new forms is Twitter. Unlike in Japan, Twitter is not chiefly for teenagers. Social interactivity is again a key; doubtless many (most?) users are drawn merely by the possible thrill of Tweeting with undisguised celebs. But beyond this there’s emerging energy in the creative potential of Twitter’s 140-character micro-format. (Quillpill, one of the new U.S. “cellphone novel” Web sites, also uses a 140-character per post limit.)

 To me, most interesting aren’t the micro-tales and poems but instead the attempts at an ongoing narrative in short bursts. Two I like are both hard-boiled crime thrillers, not surprising since the genre is conventionally lean, staccato and headlong. “Fuel Dump” by TV writer Tom Scharpling (@scharpling) wields a stripped genre-orthodox style for its wiggy premise:

Morton snapped open the briefcase and his wish was granted — four million dollars laid out in neat rows before him.

Dennis Wilson unrolled the map in the poster tube, focusing on the small red circle over a town called Jalpan.

“Fuck the Beach Boys and that bald asshole Mike Love; when this thing pans out, I’m gonna be richer than Brian,” he thought to himself.

But with “Twiller” (as in Twitter thriller), New York Times reporter, and crime writer, Matt Richtel (@mrichtel), aims more ambitiously. “Think ‘Memento’ on a mobile phone,” says Richtel, and his hectic saga of amnesia and peril unspools using texting lingo and real-time posting context with writerly jazz. It’s a juicy little read, by and large:

forgive my french: jesus #*^%& christ. I’m just outta the hospital myself, AS PATIENT. i’m walking home with JD’s chip, and some asshole..

Tackles me near an alley, punches my face, rips my earring, rifles in my purse, screams: where is chip?! (in broken english). I reach for

my penlight in my pocket and stab his eye; i run. left purse, kept chip, which was..fuck u;not saying where. someone’s reading i can’t trust

Some media critics find “Twiller” too confused and mechanical. But for me, the writer’s funky voice is payoff enough.

So far book publishers haven’t been lured by Twitter fiction. What has lured them is amateur clever bits (the forthcoming “Twitter Wit”) and, very splashily, business advice from wine blogger Gary Vaynerchuk, whose now 300,000-plus Twitter following got him a million-dollar deal. But the Twitter-to-book route is still in infancy.

Will route become highway? For fiction, I doubt it. Twitter narrative strikes me as a curio amid the insider updates and celeb-following. It lacks the urgency of generational cultural release that has driven keitai shosetsu in Japan. And Twitter may prove something of a curio itself: 60 percent of its swarms of users fail to return the next month, a grim augury. As far as Tweeting goes, that number includes me.

As for my keitai shosetsu experience, I took away another lesson beside interactivity’s impact — a writerly lesson. I reeducated myself in the weight of individual words, and the power of cutting, and cutting yet more. Writing on a computer tends to encourage flow, pacy verbal sprawl. For Japan I actually found myself ransacking old notebooks from the days when I first tried short (when I even embraced the fumy term “prose poem,” quickly abandoned as unwise for an aspiring comic author). The irony, and exercise, of salvaging faded pithy poetical scraps for new life on cutting-edge cellphones was a mighty rich one.

“The new, post-print literary media are certainly amenable to brevity,” observed the New York Times in a recent piece about fiction and the zeitgeist. “And the short story may provide a timely antidote to the cultural bloat of the past decade, when it often seemed that every novel needed to be 500 pages long …”

How about tales 500 words long?

Here, previously unpublished in English, are 3 keitai shosetsu from “I-Mode Stories”:

Meant for Each Other

You make a date through the Internet. You meet the girl for the first time at a sake bar. She gulps down a whole bottle of sake by herself. “Okay,” you think. “I guess we know what sort of problem she has. But man, is she cute.”

After two more bottles, the girl falls asleep on her bar stool. “That’s our sweetheart,” grins the bartender, shaking his head at the girl’s snores.

“You mean you know her?” you inquire, uneasily.

“Sure, she’s here every night, with a different guy,” says the bartender. “Whoopee, whoopee.” He winks.

“Really,” you reply. You eye the unconscious girl slumped headfirst on the bar counter. And you decide no matter how cute she is, this first date will also be the last, thank you very much.

And this is how you two meet, you and the love of your life. Four months later you get married and move into a lovely apartment together, where you start to raise a large and happy family.

How you get from point A to point B is a long, complicated, heart-warming, and in many ways wonderfully unbelievable story. But alas it requires someone with far greater narrative powers than mine to properly relate.

Edgar Allan Poe Rice Ball (Medieval Landscape)

Disease strikes a distant town. The victims develop loathsome sores all over their bodies; at the same time they’re maddened by extreme lascivious impulses. Down street after street door after door is splashed with a crude red cross: inside, the lunatic disfigured coupling rages on nonstop — men, women, even children — until exhausted dawn, until death.

In the hills beyond town, a monk makes his way along a darkening road. He chews a stale rice ball for his supper as he goes, so as not to interrupt his march. His sandaled feet move one in front of the other inexorably. His staff leaves a trail of dots behind him in the dusty distances. At last he comes around the side of a hill and he stops. The prospect of the dim town spreads before him. A look of disturbance moves over his face, as he slowly chews the last of his rice ball. Even here the uneasy wind carries the grisly minglings of lamentation and carnal grunting. The monk becomes watchful; he looks uneasily around him and grips his staff in both hands. Two figures are moving feverishly in the darkness ahead. They seem to prance toward him, half-naked, hideous, moaning hoarse endearments. The monk calls to his god as he raises his staff and prepares to meet them.

Woolly

A man goes for a swim in a creek. When he gets out of the water, he sees a sheep standing on the bank, watching him. The man looks at the sheep. The sheep looks at the man. Slyly, the man smiles. He checks up and down the creek. There’s no one in sight. The man steps toward the white, woolly mammal. “Here sheepy, here woolly,” he says softly. The sheep backs up slowly into the bushes, looking confused by the state the man’s in. But the sheep is only faking.

Later, the man dresses by the creek. The sheep lolls next to him, watching him, warm-eyed. The man combs his hair and says, looking down the creek in the direction of his off-road vehicle, “So that was a lot of fun. Maybe I’ll be back up this way sometime. I’ll get in touch.” He puts his comb back in his pocket and gives the sheep a quick pat. He gets to his feet. “Okay?” he says, dusting off his pants.

The sheep lies perfectly still and watches the man picking his way awkwardly down the creek into the distance. “Yeah sure, bud, I believe you,” it thinks.

Last month, Occupy Wall Street participant and Brooklyn Bridge arrestee Malcolm Harris was unable to quash a subpoena demanding Twitter hand over information about his account to the authorities. But in a surprise move this week, Twitter has come out batting for its user.

When a New York judge ruled in April that Harris did not have the standing to fight the subpoena (arguing that his tweets actually belonged to Twitter) and that there were no privacy grounds on which the individual user could refute the demand for his Twitter records, this seemed to suggest something worrying: that we have little jurisdiction over our online identities and can’t even fight for our online speech in court.

When Barack Obama blew America’s mind by declaring his support for same-sex marriage Wednesday, he explained that his views on the subject had long been “evolving.” But while evolution is a process that can take millennia, social media moves with considerably more swiftness. However long it took the White House (nudged though it was by Joe Biden’s Sunday blurt that he was “absolutely comfortable” with marriage equality) to get to that place, it took no time at all for Obama’s sentiments to become a meme.

There’s a lot about what went down with Chicago Sun-Times columnist Joe Cowley’s painfully sexist airplane rant on Twitter this weekend that’s hilarious. There was the whining that “I’m more likely to see a Squatch before I see a hot flight attendant.” There was the concern over flying in a plane with a “Chick pilot.” There was his gloriously tone-deaf response to sportswriter Sloane Martin about his comments, culminating with a demand she “hottie up that [profile] pic a bit more.” Had he added a mention of how much he loves scotchy scotch scotch, the entire tirade could still not have felt more deliriously out of time.

I tweet a lot. Sometimes I feel like I tweet more often than I have face-to-face conversations — and therein lie multiple issues that will not be addressed here (but perhaps one day, in therapy). However, in the course of constructing these 140-character-or-less nuggets of opinion, information or political agitation, never did I give much thought to whether these tweets were mine. It turns out they’re not, in the eyes of the law. For all the clamor about Twitter’s revolutionary potential in the Middle East, we have a reminder right here in New York of its revolutionary limitations.

It wasn’t that long ago that a generational social media disaster looked like “S#&% My Dad Says.” It was amusing, the way The Olds were inadvertently posting on their adult offsprings’ Facebook walls and thinking it was email. Look at them, with their lack of technical acumen and their crotchety pleas for assistance! You know what embarrassing your kids looks like now? Courtney Love.