WASHINGTON (AP) _ A pioneering strategy to stem online child pornography is threatening Internet stability because it blocks Web surfers visiting innocent sites located in the same virtual neighborhoods as those peddling illegal porn, a prominent civil liberties group says.
In a precusor to a possible legal challenge, the Washington-based Center for Democracy and Technology said it will try Thursday to compel Pennsylvania's attorney general to disclose new details about unusual efforts in that state forcing Internet providers to block visits to Web sites containing child pornography.
Lawyers for the group compared the technique to disrupting mail delivery to an entire apartment complex over one tenant's illegal actions.
Pennsylvania's attorney general, operating under a highly unorthodox state law passed last year, has so far instructed Internet providers with customers in the state to block subscribers from at least 423 Web sites around the world.
The law is unusual because it places risks of a $5,000 fine on companies providing Internet connections to Web sites with illegal photographs, not on the pornography sites themselves.
``It's sort of this weird world where we're not prosecuting the people producing child pornography,'' said Alan Davidson, associate director at the Center for Democracy and Technology.
Attorney General Mike Fisher, a Republican, has defended the law and his use of it as an effective method for preventing citizens from viewing child pornography. Citizens can file an online complaint using a form on Fisher's Web site.
``It has worked in nearly every case,'' said Sean Connolly, a spokesman for the Pennsylvania attorney general.
Only once has an Internet provider disputed Fisher's instructions, and a county judge ordered WorldCom Inc. in September to comply. WorldCom's lawyers, while saying they abhor child pornography, had objected that filters placed on behalf of Pennsylvania citizens would affect all their subscribers in North America from visiting thousands of Web sites ``completely unrelated in content and ownership'' as the pornographic material.
Lawyers for the civil liberties group and some technology experts said the strategy in Pennsylvania undermines the Internet's global connectivity by regularly blocking Web surfers visiting harmless sites that may be located on the same server computers as sites with child pornography.
They said they will seek information Thursday from Fisher about his use of the law under that state's open records statute.
In a new study to be published Thursday _ coinciding with the group's move _ a Harvard University researcher, Benjamin Edelman, determined that more than 85 percent of Web addresses ending in ``com,'' ``net'' or ``org'' share computer resources behind the scenes at Internet companies with one or more other Web sites. That is a far higher figure than previously recognized.
Edelman, who said he analyzed 30 million Web addresses over six weeks, said some Web sites share a single numerical Internet address with dozens of other sites. He said this level of sharing, which uses an increasingly common technique called ``virtual hosting,'' interferes with blocking efforts by governments.
In one extreme case, a single Web site, www.a000.net, shared its numerical address with 970,411 other sites.
Connolly, the spokesman for the Pennsylvania attorney general, said Wednesday that in such cases involving a Web site with a shared address, authorities contact the Web-hosting companies and order them _ under threat of legal action _ to pinpoint and shut down the illegal pornographic sites.