A leading lady of tell-all bloggers, Cutler came to fame just as online diaries began to proliferate. They're now a nation more than 65 million strong, collectively dishing a lot of personal dirt. Bookstores and talk shows have long trafficked in the confessions of not-necessarily-notables, but the Internet has democratized and amplified personal gut spilling. Web sites such as postsecret.com and mysecret.tv bring bathroom-wall-variety confessions, such as "I only love two of my children," "I had gay sex at church camp," and "I pee in the sink," to—and from—the masses. Meanwhile, teenagers telegraph their deep thoughts and petty observations for YouTube prowlers hungry for novelty and diversion.

Such waves of revelation are fast eroding our notions of private identity. People have always been inclined to share their secrets, to unburden their consciences, and to show off, but in times past these admissions were aimed at confidants—priests, soul mates, diaries. Telling secrets can be therapeutic, but when confession targets the masses, what's really being processed, and who benefits from the disclosure?

Ironically, humans now enjoy more privacy than ever, says Aaron Ben-Ze'ev, president of the University of Haifa and author of Love Online: Emotions on the Internet. "Two hundred years ago, when people lived in villages or very dense cities, everyone's behavior was evident to many and it was extremely hard to hide it," he says. Today, e-mail and "chatting" online allow for completely anonymous interactions. We can talk and make plans without the whole household or office knowing. But if we're so able to keep things to ourselves, then why are we doing exactly the opposite?

For those engaging in online conversations or message-board discussions, the Internet can be more disinhibiting than the stiffest drink. Electronic disclosure eliminates the normal self-censorship mechanisms that have evolved over human history—and therein lies the primary explanation for the Jessica Cutler phenomenon.

"We've been shaped to be very sensitive to each other on a face-to-face basis," says Daniel Wegner, a Harvard psychologist. When someone is in front of you, you can read how they're reacting to your admissions, keeping track—as you're hardwired to do—of whether they're comfortable, disapproving, or rapt. But when you're alone in a room and typing on a computer, explains Wegner, it's easy to forget there's somebody on the other end of the line and become oblivious to the consequences of sharing information. "When people post to blogs, they may be thinking, 'I'm not going to worry too much about who the target of my revelation might be; I'm just going to go ahead and let go.' " Hairdressers, bartenders, and strangers on a train have long been recipients of anonymous confessions, but they're also participants who keep you from getting too lost in your head or revealing too much.

This is the trap that snared Cutler, who never expected an audience beyond her close, like-minded friends. "The big problem as I saw it was using e-mails, since those could get forwarded," says Cutler. "I thought my blog was a more private way to share stuff."

It's one thing to risk full exposure, but quite another to eponymously title your proudly unexpurgated blog. In I Can't Believe I'm Still Single: The Eric Schaeffer Blog, a 45-year-old screenwriter and director intersperses tales of dating mishaps, recipes, musings on Gandhi, and an excruciatingly detailed account of a visit from a professional dominatrix. (A defense of his preference for younger women reads: "I don't get mad when women like black guys, or young guys or buff guys, it's their preference. God bless them. STOP GETTING MAD AT ME AND THE REST OF US 45 YEAR OLD MEN WHOSE CUT OFF IS 36 OKAY?!!!")

In exchange for his brutal honesty, he's suffered a barrage of online criticism and mockery. Though he considers most of his life's work to be infused with autobiographical elements, he did pause before writing the blog and a memoir: "I thought, do I want everyone to know the deep recesses of my sexuality, my parents, all that stuff? The fear was that then people would judge me, that perhaps they wouldn't like me. But I didn't want to act out of fear, so I asked myself, is there a positive reason to do this? And that would be connecting to people who appreciate me expressing myself and revealing my weaknesses."