For evidence that digital information, once set free, cannot be controlled, consider the steamy video of Brazilian supermodel Daniela Cicarelli making out with her boyfriend on a Spanish beach and in the water just off shore.
The couple persuaded a Brazilian court last fall to force the video-sharing site YouTube to remove copies, but other users simply resubmitted the video through their free accounts.
Earlier this month, Internet service providers in Brazil, responding to the judge's order, briefly blocked access to YouTube entirely. But by then other Web sites already had the video, and many in Brazil even had stored personal copies on their computer hard drives.
Safekeeping information - video, photographs, documents - will become even tougher with the emergence of additional "Web 2.0" services designed for users to easily share data. Society may have good reasons - such as privacy, security or taste - for wanting to keep the lid on some types of information, but it only takes one individual to overrule that desire.
"There are more and more ways to distribute information, but very few new approaches to keeping information secret," said Steven Aftergood, senior research analyst at the Federation of American Scientists' Project on Government Secrecy. "Paradoxically, the attempt to suppress information often tends to draw greater attention to it, so a government agency or an unhappy celebrity or anyone else may decide that challenging disclosure is counterproductive."
Indeed, the Cicarelli clip became even more popular after the YouTube ban made headlines worldwide, and users in Brazil and beyond posted it to a slew of other Web sites not subject to the Brazilian court order. Faced with international outcry, the judge ultimately lifted his YouTube ban.
But the Cicarelli video is hardly the only example of information circulating out of control.
Iraqi authorities released official footage of Saddam Hussein's Dec. 30 hanging, but cell-phone video taken by a witness quickly made the rounds online, this one showing guards taunting Saddam in the final moments of his life. One copy at Google Inc.'s main video site had been viewed more than 15 million times by Tuesday. The clip also was available through Revver Inc. and Google's YouTube.
Last summer, in a gesture to researchers, Time Warner Inc.'s AOL released the Internet search terms that more than 650,000 of its subscribers had entered over a three-month period. Senior executives quickly pulled the data, saying the release had not been properly vetted, but copies were already circulating and Web sites have even been created specifically to query that database.
And a few years ago, a hacker broke into Diebold Inc.'s servers using an employee's ID number and copied documents, some of them raising security concerns about the company's electronic-voting machines. Diebold unsuccessfully sued to have copies removed from other Web sites.
The Internet makes broad dissemination quick and easy. And because digital copies are exact copies, details don't get lost or misstated in retellings the way they might have before.
Tools for producing digital evidence are also more broadly available. The unauthorized Saddam video might not have been possible a few years ago without cell phones and digital cameras that can record video - a standard feature these days.
The Cicarelli video came from an old-fashioned paparazzo but sites like YouTube allow more people to watch. Controls to limit copying are easily defeated using third-party software for converting Flash video into files that can be stored and passed around.
Even the stanchest advocates of data free-flow worry about the ease of distribution.
"There are publications that can be an act of aggression, it can be part of a vendetta against an individual, or it can be an act of incitement against a hated minority," Aftergood said. "There are reasons why the best, most reputable media outlets have editors. With the ease of publication, today we are losing some of that editorial filter."