The EFF is a plaintiff in the lawsuit challenging COPA, which was meant to shield minors from Web sites that offer sexually explicit content. The high court struck down provisions that required sites to offer such content only to registered users or people who sign-in first, saying that filtering software is sufficient to keep the content away from children.
In seeking the search data, government lawyers are hoping to show a federal court in Pennsylvania that sexually explicit material is easily accessible through search engines and is not adequately blocked by filters.
To Andrew B. Serwin, a partner in the San Diego law firm Foley & Lardner LLP and a consultant on privacy issues to Internet companies, trust and privacy are "two sides of the same coin."
"Whether you put it in terms of trust or privacy, the concern is that the government could use non-personal information as a basis for a warrant to get personal information," Serwin said.
Once government prosecutors get non-identifiable information, they could see patterns that they decide are suspicious, and then go back to subpoena specific data that could identify people whose searches fell within those patterns.
"It is not beyond the realm of possibility that the government would say, 'we know these searches occurred, so lets have more information,'" Serwin said.
There is no indication that the Justice Department is heading in that direction in the current case, but providing such large amounts of data could be the beginnings of a trend, the lawyer said.
The issues in the current case also have no implications for national security and fighting terrorism, Serwin said. Such issues are handled through the Patriot Act, which gives federal law enforcement the right to demand information in secrecy.
"We're not dealing with a Patriot Act request, in which case we wouldn't have heard about it," Serwin said. "This is not a national security issue."
The question of trust and Internet businesses has spread beyond U.S. borders to places with less political freedom. Microsoft this month was criticized for taking down from its blog-hosting service MSN Spaces, the blog of an outspoken Chinese journalist Zhao Jing. The company said it was complying with Chinese laws.
In September, Yahoo gave information about journalist Shi Tao's personal email account to Beijing, which later jailed him for 10 years on charges of divulging state secrets.
