Internet blocking programs (also known as "filtering programs" and "censorware") are computer programs designed to prevent access to certain Web sites. N2H2 develops, markets and licenses a blocking program that prevents computer users from accessing content that has been categorized by N2H2 as objectionable. Part of the program is a list of sites to block -- a "block list" –- that contains hundreds of thousands of Web sites representing millions of pages of Web content.

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Blocking programs such as N2H2's are notoriously inaccurate, often preventing access to sites that should not be blocked while failing to block many that should. And blocking programs are increasingly used in public schools and libraries and by various government agencies. Because of this growing public role, it is especially important that the public be able to check and evaluate how these programs work, and what Web sites are being blocked. However, most blocking program companies, like N2H2, consider their block lists to be proprietary trade secrets, and will only distribute them in an encrypted form that the program itself can understand but people can’t. As a result, current and potential customers, including schools and libraries, cannot effectively evaluate the program’s accuracy, and students, library patrons and other citizens forced to use blocking software are kept in the dark about the extent of web site filtering.

Accordingly, I seek to extract, analyze, and publish this list, and to further share the tools and methods I used to do so. But until the court confirms my constitutional right to engage in these activities -– a right that the DMCA and other legal developments have cast into doubt -– I cannot safely conduct this kind of research, much as I believe that such a project is in the public interest. In particular, I fear that N2H2 might accuse me of infringing their copyrights, of violating the Digital Millennium Copyright Act (DMCA), of breaching the software license that customers must agree to in order to install the N2H2 program, and/or of misappropriating N2H2's trade secrets (which N2H2’s license agreement makes customers promise to protect).

For more details about the case, including a full copy of the complaint, see postings at the following pages:
 http://cyber.law.harvard.edu/people/edelman/ edelman-v-n2h2
 http://www.aclu.org/news/2002/n072502a.html
 http://www.aclu.org/issues/cyber/Edelman_N2H 2_feature.html