In recent years, the porn industry has gotten screwed harder than a beleaguered Marquis de Sade heroine, first by rampant piracy, then by a vicious recession. Now that thousands of former customers believe money shots should be as free as Lady Gaga singles and New York Times editorials, the industry's revenues are dropping, production is declining and thousands of talented but underutilized adult performers are fantasizing about a stimulus package of their own. But even if lesbian MILF bondage is no longer the foolproof cash cow it once was, there's still one subspecies of porn that can reliably open our wallets.

How strong is the allure of the celebrity sex tape? Just ask John Edwards. Blessed with the raw animal magnetism of a well-groomed Maltese, the one-time Democratic presidential candidate is certainly not the first person you'd think of if you were asked to name America's most bankable porn star. But according to Andrew Young, the former Edwards aide who temporarily possessed a copy of a 15-minute sex tape his boss made with his personal videographer Rielle Hunter, at least one entrepreneur offered Young "gigantic amounts of money" for the unlikely artifact.

Combining technology, exhibitionism, populism, fame, DIY ethos and the possibility of a quick buck, the celebrity sex tape celebrates everything we celebrate; it's the signature art form of the age. It also solves porn's greatest challenge in an age of visual ubiquity: how to retain an aura of illicitness.

Throughout the 20th century, even as photographs, films and video proliferated, various constraints limited the amount of imagery available to us. In the world of old media, devoting 70 editorial pages to, say, celebrity nose-picking photos, was an extravagance not even the National Enquirer could afford. Compiling gruesome galleries of headless motorists, armless torture victims and kittens becoming lunch was not considered a particularly noble way to inform the public or attract department-store advertisers. Economics and taste kept us optically innocent.

But visual information wants to be free, too. In the late 1990s, as the web started shifting from a primarily text-based medium to a far more image-heavy one, sites like Rotten.com and StileProject.com pushed the limits of the IMG tag. Suddenly, truly exotic examples of the forbidden were as accessible as Miss July centerfolds. And porn, which for decades had functioned as our primary commercialized form of forbidden imagery, the stuff we looked at when we wanted to look at something we weren't supposed to look at, proliferated so wildly it lost much of its transgressive power.

Now porn is overexposed, a little too permissible, a little too easily obtained. Which brings us back to the celebrity sex tape. Compared to much of the commercial porn that's being produced today, celebrity sex tapes are notable for their chasteness and sense of restraint. They tend to limit the action to just two participants, who couple as sweetly and kinklessly as a pair of cuddly bunnies.

The first 40 minutes of Pam and Tommy Lee: Hardcore and Uncensored, the 1998 tape that became the genre's first huge commercial hit, contained less risqué material than the average Lifetime Channel romantic comedy. Thanks to their ostensibly confidential nature, however, celebrity sex tapes do manage to re-establish porn as something that's at least mildly forbidden.

It says something about the exhibitionistic age we live in that the sex tape has emerged as a totem of privacy, an intensely personal object. Every sex video, after all, presupposes an audience of some kind, even if that audience is only intended to be the people making the tape. If you aren't interested, on some level, in being projected, publicized, cast as a performer engaged in a performance, why engage in porn karaoke in the first place?

Still, in most cases celebrity sex tapes see the light of day thanks only to the efforts of nosy computer repairmen, unscrupulous house painters or opportunistic ex-lovers—or at least that's the pose invariably struck. And if we don't completely believe that line, we nonetheless literally buy it. One Night in Paris wasn't 2005's bestselling porn video because it offered more impressive carnal showboating than the 15,000 other porn videos released that year. It was the bestselling porn video because it gave people a chance to see imagery that Paris Hilton allegedly preferred to keep private.

Out in the American heartland, a vast array of tubby octogenarian swingers, clothing-optional sororities and June Cleaver types who enjoy wandering the aisles of Wal-Mart half-naked exhibit their wares on the web for fun and profit. But in decadent, hedonistic Hollywood, few celebrities attempt to capitalize on the fact that you no longer have to be a porn star to be a porn star. For an hour's work, Brad Pitt and Angelina Jolie might conceivably earn upward of $50 million. If they could persuade Jennifer Aniston to join them, they'd all be billionaires.

For now, lesser-known exhibitionists have little to worry about. The stigma attached to celebrity sex tapes remains mystifyingly, comically strong. Paris Hilton, no one's idea of a blushing wallflower, claims that the distribution of her sex tape "humiliated" her. Kim Kardashian says her sex tape "devastated" her and caused her stepdad, Bruce Jenner (whose enthusiastic participation in the reality series I'm a Celebrity . . . Get Me Out of Here! would seemingly qualify him as impossible to embarrass), to stop talking to her for three weeks.

Carrie Prejean, whose series of eight solo sex tapes remains unseen by all but an ex-boyfriend, her mom and perhaps a few dozen lawyers, beauty pageant officials, gossip columnists and porn-industry entrepreneurs, characterizes them as the "[eight] biggest mistake[s] of [her] life." Kid Rock filed a lawsuit to prevent the release of a sex tape he and fellow rocker Scott Stapp appeared in, apparently determined to protect his reputation as a horny but demure stripper-humper.

Even O.J. Simpson, for whom any visual evidence of amicable relations with women should be considered a plus, considers the celebrity sex tape morally repugnant. "This tape is garbage, and we can prove it," his lawyer exclaimed in 2006 when a video purporting to depict the former football great with two women was released. "O.J. wouldn't do anything like this."

No doubt a legitimate desire for privacy informs such attitudes, but consider the messages celebrity sex tapes end up conveying most explicitly. Sex is shameful and embarrassing. It can damage your character. It's best kept behind closed doors. It's easy to see how antiporn groups like the American Family Association might enthusiastically embrace the genre, but the rest of us are faced with a difficult, uncomfortable truth: our most publicized, bestselling porn titles are designed not to incite desire or celebrate sexuality but to embarrass and humiliate celebrity exhibitionists, or at the very least demystify their carefully cultivated personas.

This is not a sign of a healthy culture, but at the least the specter of the John Edwards sex tape may threaten to force us to confront the troubling, reactionary turn our taste in porn has taken. As of late February, the tape remains in the custody of Superior Court Judge Abraham Penn Jones in North Carolina, who is presiding over a case in which Rielle Hunter is attempting to reclaim possession of it. But if the tape is ever released commercially, it will likely sell hundreds of thousands of copies to rubberneckers eager to witness the horrific scenes of passion it presumably contains, instantly establishing a preening 56-year-old former senator as our most popular porn star.

And if the grim reality of that nightmare can't reignite our passion for hardcore S&M orgies, interracial foot fetish videos and other more wholesome forms of pornography, then nothing can.

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