You won't find WikiLeaks' biggest impact in any specific story the site has exposed. You'll find it in the bracing fear of what the place might publish next. That anxiety, more than anything else, explains the arrest of Bradley Manning, the soldier who allegedly leaked that infamous video of the airstrikes that killed two Reuters employees in Baghdad. The government doesn't want to deal with a world where a disillusioned functionary can spill secrets so easily, and it's doing everything it can to bring back the days when leaking a story was far harder.

For those who tuned in late: WikiLeaks is an online operation that lets whistleblowers publish damaging documents without anyone—not even the people who run the website—learning who the leaker is. Besides the Baghdad footage, its revelations have ranged from the emails that set off the climategate scandal to the Standard Operating Procedures manual from the U.S. prison at Guantanamo Bay. The authorities arrested Manning after he told an informant that he had sent the site the video and a trove of other damaging information, including thousands of U.S. diplomatic cables. The cables have not yet materialized, and WikiLeaks co-founder Julian Assange says he doesn't have them.

It's not yet clear that Manning actually is the leaker, as opposed to merely being a braggart. But I hope he avoids a jail term either way. The Obama administration has brought an ugly double standard to the misdeeds committed during the Bush years. It has passed up opportunities to prosecute those crimes on the grounds that it wants "to look forward and not backwards," but it has shown no such restraint when it comes to prosecuting the people who exposed those crimes in the first place. Having brought charges against two other leakers, including NSA whistleblower Thomas Drake, the feds now seem set to do the same thing to Manning. Meanwhile, WikiLeaks itself has been the subject of an Army counterintelligence report, which suggested that "identification, exposure, termination of employment, criminal prosecution, [or] legal action against" whistleblowers could "damage or destroy" the belief that WikiLeaks protects its sources' identities, and will thus "deter others considering similar actions from using the Wikileaks.org Web site." (We know about the report because it appeared—where else?—on WikiLeaks.)

WikiLeaks has attracted a wide range of criticisms, and not just from the knee-jerk defenders of the institutions it exposes. A similar public disclosure site, Cryptome, has published texts allegedly written by "A WIKILEAKS Insider," who accuses the organization of failing to protect its leakers and of misleading the public about its finances. But most critiques of WikiLeaks boil down to one of two complaints. The first is that it distributes information that shouldn't be spread; the second is that it distributes claims that aren't accurate. Put another way, people complain that it's too truthful and that it isn't truthful enough.

The second criticism hasn't come up as often as you might expect. When WikiLeaks publishes an article analyzing the documents on the site, the writer's claims are dissected and denounced as widely as any other arguments on the Internet. But with rare exceptions, the documents themselves tend to be accepted as legitimate. Pundits may debate the meaning of the Baghdad video, the climategate emails, or the Guantanamo prison manual, but their provenance has been well-established. Given the enemies that WikiLeaks has made, you might expect that by this time someone would have attempted to discredit the outfit by feeding it phony data. But if this has been tried, there's no sign yet that the site has taken the bait. As a means of distributing raw information, WikiLeaks works.

For some critics, it works too well. Many people argued that WikiLeaks went too far in 2008, when it posted the technical details of some of the jammers the military had used to stop insurgents from detonating IEDs in Iraq. The decision didn't necessarily put lives in danger—by the time the material appeared, the jammers in question had largely been superceded—but it's hard to see what it was supposed to achieve either. Exposing information can carry risks, and in that case the risk wasn't worth it.

But concealing information can be risky as well. Thanks to WikiLeaks, Chinese citizens have access to information about unrest in Tibet; thanks to WikiLeaks, Kenyans can read about the extrajudicial killings committed by their own police. Thanks to WikiLeaks, we have evidence of corruption in the Kaupthing Bank in Iceland, and of deadly toxic dumping off the coast of Africa. WikiLeaks has expanded our knowledge of how prisoners are treated at Guantanamo, how the CIA tries to manage public opinion in Europe, and how some prominent climate scientists talk about their critics. And if Thomas Drake had revealed the NSA's illicit surveillance program to WikiLeaks instead of the Baltimore Sun, he might not be facing a prison sentence today. You can complain about some of the editorial decisions that WikiLeaks' managers have made, but as with the free press in general, we're better off with the site than without it.

Above all, we're better off now that the large, hierarchical institutions where potential leakers dwell have one more reason to look over their shoulders. At some point, even the most thick-headed, slow-moving bureaucratic dinosaurs just might recognize that they're living in a new environment, one where corrupt corporations and government agencies are no more able to control the flow of embarrassing information than record companies can control the flow of digital music files. Just as the online MP3 swap meet continued to thrive after downloaders started landing in court and Napster was effectively destroyed, the revolution that WikiLeaks represents won't die even if Manning is imprisoned and Julian Assange's site shuts down. Thanks to the Internet, a new wave of grassroots journalists, and a global network of human rights activists, it's less risky than ever before to release incriminating information anonymously. The result will be a world where it's easier not just to expose misbehavior but to deter it.

Managing Editor Jesse Walker is the author of Rebels on the Air: An Alternative History of Radio in America (NYU Press).