The terrorist plot to blow up as many as 10 airliners while they were flying over the Atlantic Ocean from Great Britain to the United States was thwarted largely as a result of intercepted communications and surreptitious observations.

British, U.S., and Pakistani investigators tapped into the telephones and hacked into the computers of the alleged terrorists, tracking the trail of money supporting them along the way. Among other things, the authorities spotted these individuals clicking around the Web to learn of nonstop flights from the U.K. to the U.S. that left around the same time and that would be suitable for their plot.

In other words, they spied.

It’s difficult to imagine even the most resolute civil libertarians objecting to invasions of privacy such as this that prevent mass murder. But in the vast majority of cases, the line isn’t as clear-cut.

Among recent court cases in the U.S. testing this boundary involves an issue that couldn’t be more mundane: embroidery and the software consumers can use to help with their embroidery projects. In July, the Embroidery Software Protection Coalition (ESPC), a group of embroidery software and design manufacturers, went after individuals participating in an online discussion group about embroidery.

The group, EmbroideryOrganizationInformation (http://groups.yahoo.com/group/EmbroideryOrganizationInformation), is a Yahoo! Groups discussion group that was set up in response to piracy and copyright infringement charges made by ESPC against those who share embroidery designs obtained from embroidery software and from embroidery design companies.

Many of the participants have elected to participate in the discussion group on an anonymous basis. In response to this, ESPC obtained a subpoena to force Yahoo! to reveal the identities of these people in addition to filing defamation claims against individual members for what they wrote.

The Electronic Frontier Foundation (EFF), in turn, filed a motion to block this subpoena, which it described as “brazen” and “heavy-handed.”

“ESPC’s shotgun approach is aimed not at redressing defamation but at intimidating those who have sought to raise public awareness of its ham-fisted tactics,” said EFF staff attorney Corynne McSherry. “The First Amendment forbids such abusive use of the courts and the discovery process.”

EFF (http://www.eff.org), based in San Francisco and founded in 1990, is one of the most visible voices on the Internet in promoting the rights of individuals who use the Internet.

The ESPC case is the latest of EFF’s efforts to protect anonymity online. “The right to engage in anonymous communication is fundamental to a free society,” said McSherry. “It’s critical that judges resist these attempts to turn courtrooms into vehicles to harass and intimidate people out of speaking their minds. Thankfully, court after court has recognized that plaintiffs can’t pierce anonymity just because they don’t like what someone has said.”

ESPC has a different take on this. It sees itself as fighting piracy and the illegal sharing of embroidery designs. “It is common for embroidery designs to be copied and sold at below market prices to end users,” it states at its Web site (http://www.embroideryprotection.org). It says that getting embroidery designs for free or next to nothing is “stealing and it is illegal and unethical.”

The group doesn’t mince words, though it doesn’t seem clear on its target audience. “While sailing the high seas of the Internet, be careful of the pirates … they are there lurking and waiting for you.”

Internet anonymity has a long tradition, and anonymity in general has an even longer one. As EFF said in its motion to quash the subpoena, “Internet discussion groups are forums for the exchange of information and ideas. They fulfill the same function in modern America as local newspapers and printed broadsides in colonial America and coffee house publications like the Tatler and Spectator in 17th century England. Participants sometimes use their own names but often use pseudonyms, just as Benjamin Franklin used ‘Silence Dogood’ and many other pseudonyms.”

In its background information about anonymity, EFF cites the famous 1995 Supreme Court ruling in McIntyre v. Ohio Elections Commission:

“Protections for anonymous speech are vital to democratic discourse. Allowing dissenters to shield their identities frees them to express critical, minority views … Anonymity is a shield from the tyranny of the majority. … It thus exemplifies the purpose behind the Bill of Rights, and of the First Amendment in particular: to protect unpopular individuals from retaliation … at the hand of an intolerant society.”

You can read further details of this case from both sides at the Web sites of ESPC (http://www.embroideryprotection.org) and EFF (http://www.eff.org/legal/cases/ESPC_v_Ebert).