WASHINGTON (Reuters) - A Washington nonprofit group was scheduled on Tuesday to argue against a Pennsylvania child-pornography law that has unintentionally cordoned off wide swaths of the Internet for users in and out of the state.

The arguments will be made before a federal judge in Philadelphia.

Among the 600,000 sites blocked are a community recreation center in Bradford County, Pennsylvania, a tribute to a Paraguayan soccer player, reviews of opera singer Alice Baker, and a vendor of "family edited" DVDs that have nudity and other content removed, the Center for Democracy and Technology said in a court filing.

CDT, the Pennsylvania chapter of the American Civil Liberties Union and Internet provider Plantagenet Inc. have sued to overturn the law, arguing that it amounts to an unconstitutional restraint on free speech.

The law allows district attorneys to require Internet providers to block access to a Web site they believe contains child pornography. State investigators have filed more than 500 requests since April 2002.

But the blocking orders have rendered inaccessible hundreds of thousands of other sites that share the same address, CDT said. Out-of-state users are affected as well because Internet providers such as Time Warner Inc.'s America Online have no easy way to only restrict access for customers in the state.

A better approach would be to sue the pornographers directly, CDT said, or ask the company that hosts the content to remove it.

State investigators said prosecution is expensive and difficult, especially if the suspect is located overseas. Getting a foreign Web-hosting company to cooperate can be difficult as well, Acting Attorney General Gerald Pappert said in a filing.

Internet providers can use a variety of techniques to reduce overblocking, the attorney general said, such as filtering out specific pages rather than entire numerical addresses such as 209.25.162.15 that underpin domain names like www.example.com.

© Reuters 2004. All rights reserved. Republication or redistribution of Reuters content, including by caching, framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.

For more information: