A FEW years ago I got this note from a mother in my son’s class. “Hey, we both end our e-mails with ‘Carpe Diem’! Hope the parents in class won’t confuse us, ha-ha!” Naturally I thought she was kidding, and wrote back saying our different names might be a tip-off we were not the same person. “Oh, sure,” she said, “but I’ve used ‘Carpe Diem’ forever. People know me by that one. It would be great if you used something else from now on. Thanks!”

After briefly considering the alternative “Carpe Diem, You Control Freak,” I continued ending my notes as I had, and the mother dropped the issue. But it was the first time I realized how fraught that little epistolary goodbye can be.

In a medium where it is often oddly difficult to interpret tone, where the lines of friendship, love and business are easily muddied, and where people are sometimes a little too eager to shine brightly in the drab sludge of daily missives, something as seemingly trivial as an e-mail signoff can loom large. It can be a clue to both the personality of the sender and the standing that the recipient has in the sender's social universe. It can enlighten, amuse and enrage — sometimes all at once.

Quirkier signoffs can be every bit as much a personality signifier as clothing — the equivalent of a leather jacket or Jimmy Choos. Katrina Markoff, who owns Vosges Haut-Chocolat, closes her e-mails with the words “Peace, love and chocolate.” (“She believes she can bring peace to the world through chocolate,” her spokesman says.)

I used to think my friend Bishop Savas of Troas, the director of the Office of Society and Culture of the Greek Orthodox Archdiocese of America, signed his e-mails with a “+” instead of an X for kiss because it was his unique form of proper, churchly affection toward me. Um, no. “This is actually a common signoff among those in the church, but please, don’t let that disturb your theory,” he generously explained.

On the other side of the theological aisle, David Hirshey, executive vice president at HarperCollins, tends to close his e-mails with the words “Stay Jewish” — “though mostly with friends who are Gentiles,” he added. “I find it works best when the person’s last name is something like O’Hara or Soprano.”

People go through periods where they try on different closes like hairstyles. “Norman used to use ‘Cheers,’ and I tried to appropriate it when he died,” the writer and artist Norris Church Mailer said of her husband, Norman Mailer. “It just wasn’t me.” For now, Ms. Mailer is sticking with the lowercase xx — “which are not really kisses but a placeholder, as if I don’t really know how I feel about this person, and they can apply whatever meaning they choose.” But Ms. Mailer did approve of the signoff I was currently trying on, “Be Fabulous.”

“I love that!” she said. “Of course, I’ve lived in Provincetown for the past 35 years.”

Confusing for many of us, particularly in business relationships, is the question of familiarity. People will start with “Sincerely” and work their way up — “Regards,” “Best,” “Warmly,” “Fondly.” But then there’s inevitably a point where a decision needs to be made.

“I’ll be having a back-and-forth e-mail — I’ll get ‘Best’ and ‘Regards’ and ‘Cheers’ — and all of a sudden I get ‘Love,’ ” said Will Schwalbe, a co-author, with David Shipley, the editor of The New York Times’s Op-Ed page, of the book “Send: Why People Email So Badly and How to Do It Better. “And then I’m tortured. Is it just a dumb slip? Or is it a Freudian slip? And if you return the ‘Love,’ it’s like an arms race — how do you step back without insulting someone?”

Thomas Mallon, a novelist and the author of “Yours Ever,” a book about some of the world’s best letter-writing, said: “I’ve learned over time that X-ing and O-ing in a business relationship, no matter how much you may like the person, is probably buying yourself trouble. Because there will come a time when you have contentious business — and then what?”

And as mortifying as the runaway train of escalating intimacy can be, the complete misplacement of it can be worse — so easy to do when one of the most reflexive signoffs is XOXO. (Startlingly, even William F. Buckley Jr. used it.) Eric Poole, a Fox executive and the author of “Where’s My Wand?” — a memoir about growing up gay and Baptist — still shudders a little remembering the day when he “accidentally signed XOXOXO to my straight male boss. To which he replied, ‘I’m flattered, but let’s take it slow.’ ”

And Karen Karbo, a journalist and novelist, admits she has bestowed many accidental XOXOs over the years. “But the worst was when I was in the middle of the hairiest divorce imaginable and I shot off an accidental XOXO and the ex was on my doorstep within a half hour, sure this meant we were reconciling.” Then again, in established relationships, it’s always better to err on the side of warmth.

The writer Marjorie Ingall recently found a press release that her husband, Jonathan Steuer, had forwarded to her with the note, “Thought you’d be interested,” and it was signed, “Best, J” — to which she replied, “What am I, your accountant?”

It is, in fact, the reflexive nature of closes that frequently trips us up. “I recently changed my standard ‘Cheers’ signoff after noting that it had been automatically appended to e-mails breaking up with a longtime girlfriend, discussing the plans for my mother’s cremation and threatening my insurance company with a lawsuit,” my friend Spencer noted. “I’ve also learned that ‘Cheers’ doesn’t work well in any e-mail that includes the words ‘stage four.’ ”

What makes Ms. Ingall a little nuts are the wise quotes that turn out to be entirely fictitious. “When people use ‘Be kind, for everyone you meet is fighting a hard battle — Plato,’ I want to be all, ‘You know Plato never said that, right?? There’s this thing called fact-checking, look into it.’ ”

She is also not a fan of the politically correct signoff. “If the bottom of your e-mail says, ‘Please consider the environment before printing out this e-mail,’ you should know that makes me want to print out the e-mail — which I was not going to do because who prints out e-mail? Don’t flatter yourself!”

I find myself thinking, Sing it, sister, as Ms. Ingall rants; not surprisingly, we both spend perhaps a little too much time on e-mail. And that’s the problem, Mr. Schwalbe said. This virtual world of communication has become our real world, and we read all sorts of meaning into it because — here’s a shocker for you — many of us are not superclear communicators.

“We need to cut the world more slack — and ourselves less,” Mr. Schwalbe said. “There’s a very practical reason. On the one hand, we need to pay attention to how we sign off. Are we being pleasant? Sometimes an exclamation point makes the world a better place. But when we see e-mails coming to us, we don’t need to be the Style Police. People are not e-mailing in an atmosphere of monastic concentration. We’re all doing a million things. So no finger-wagging. It’s a recipe for unhappiness.”

No one wants to create angst over a signoff, which, after all, is usually just a way to ease the transition to [SEND]. So, Cheers, Yours Truly, Carpe Vino, Be Fabulous, XXOOXXOOXXOO and, if you’re reading this online, don’t print it.