Using the Internet to hide, groups like Anonymous spread sensitive materials.

Oakland, USA - Masked protesters led small, peaceful rallies in cities around the world Saturday as part of a protest by an online movement calling itself Anonymous. The organization declared "war" on the Church of Scientology in January because of the church's "suppression of dissent" on the Internet.

Some tactics employed by Anonymous have proved controversial, including attacks against Scientology websites and unauthorized circulation of church materials. The church also accuses the movement of mailing fake anthrax letters and making bomb threats – charges rejected on Anonymous websites.

"I don't know who sent [the threats], but the point is that whoever are the ringleaders [of Anonymous], they are creating these emotions and are causing this to occur, and they have to be responsible for it," says Karin Pouw, spokeswoman for the Church of Scientology.

The church has a history of aggressive litigation, but this time it's up against a new type of Internet phenomenon that's evolved to evade court orders and censorship measures. Clever use of technology is allowing new activist groups like Anonymous and the whistle-blower website Wikileaks to agitate without a centralized leadership and an identifiable membership.

These tactics of anonymous activism have given a new voice to dissidents living under authoritarian regimes in Burma (Myanmar) and China. But similar methods are now challenging the legal systems of democratic governments as well, upsetting the ability of judges to balance freedom of speech against competing claims of privacy and public safety, argue some experts.

"It's one thing to defy communist elites in China. It's something else to defy legally enacted information controls in a democratic country," says Steven Aftergood, head of the Project on Government Secrecy based in the District of Columbia. "If you value privacy or copyright or proprietary business information, then you understand that there is a place for nondisclosure."

The Internet, from its creation, has inspired strong resistance to information controls of any sort. The rallying cry "information is free" is shared by both Wikileaks and Anonymous. Right now, they are prevailing.

Last Thursday, a Florida judge denied a request by the Church of Scientology for a restraining order that would have prohibited some individuals from protesting within 500 feet of Scientology buildings. The judge noted that the identity of those making threats could not be determined. Legal threats to enforce copyright have also failed to stop the posting of a video of Tom Cruise speaking at a Scientology event.

But the real game-changing decision came last month, when a California judge backed down from an attempt to shut down Wikileaks. A Swiss bank had sought an injunction against Wikileaks after it published leaked private bank records purporting to show complicity in tax evasion. The judge's shutdown attempt backfired, as Wikileaks gained notoriety and quickly rerouted readers to mirror sites. "The judge in effect said that the law is helpless to deal with this phenomenon," says Mr. Aftergood.

Yet the courts haven't been entirely neutered by Internet anonymity, Aftergood and others say. For one thing, sources of information can be revealed with the help of Internet service providers.

For a time, however, technology has outpaced the law to some degree, and that's OK, says David Ardia, director of the Citizen Media Law Project at Harvard Law School in Cambridge, Mass. "I wouldn't say that today, just because technology developments have made it practically impossible for legal systems and nation-states to have power over [determined] actors, that that's going to be the case tomorrow," he says.

Indeed, laws may eventually have to adapt. "It calls into question the approach that most legal systems have, which is to hold the individual liable and force them to pay monetary damages," says Dr. Ardia.

Ardia and others express concern that these new legal conundrums will provoke a harsh response that could curb free speech. For instance, in response to cyber-bullying online, a Kentucky state representative introduced a bill requiring anyone who wants to post a comment on a website to give ID and contact information.

Rather than new laws, self-policing and community codes of ethics may be more practical responses to anonymity's challenges.

In the case of Anonymous, a public chiding from one supporter may have helped redirect the movement. Mark Bunker, a longtime Scientology critic, posted an online video urging Anonymous to stop attacks against church websites. "I thought they'd lash out at me, and instead they've reformed and are doing an amazing job right now," he says.

The Church of Scientology released a video last week, however, claiming ongoing harassment, including 10 acts of vandalism and eight death threats against church members. An Anonymous website cast doubt on the claims.

For its part, Wikileaks has not been associated with violent threats or attacks of any sort. It does, however, stake out a position that recognizes no legal limits on free speech.

"History shows that censorship requires censors who define what is and who is 'good.' ... Such power is quickly corrupted," e-mailed Jay Lim, a spokesperson. "Knowledge is not a good. It is unique, in a class of its own, and as creator of all law, it must be placed beyond law."