The filtering programs also miscategorized a large number of sports Web sites.  These included:  a site devoted to Willie O’Ree, the first African-American player in the National Hockey League, http://www.missioncreep.com/mw/oree.html, which Websense blocked under its “Nudity” category; the home page of the Sydney University Australian Football Club, http://www.tek.com.au/suafc, which N2H2 blocked as “Adults Only, Pornography,” Smartfilter blocked as “Sex,” Cyber Patrol blocked as “Adult/Sexually Explicit” and Websense blocked as “Sex”; and a fan’s page devoted to the Toronto Maple Leafs hockey team, http://www.torontomapleleafs.atmypage.com, which N2H2 blocked under the “Pornography” category. 7.  Conclusion:  The Effectiveness of Filtering Programs Public libraries have adopted a variety of means of dealing with problems created by the provision of Internet access.  The large amount of sexually explicit speech that is freely available on the Internet has, to varying degrees, led to patron complaints about such matters as unsought exposure to offensive material, incidents of staff and patron harassment by individuals viewing sexually explicit content on the Internet, and the use of library computers to access illegal material, such as child pornography.  In some libraries, youthful library patrons have persistently attempted to use the Internet to access hardcore pornography.

Those public libraries that have responded to these problems by using software filters have found such filters to provide a relatively effective means of preventing patrons from accessing sexually explicit material on the Internet.  Nonetheless, out of the entire universe of speech on the Internet falling within the filtering products’ category definitions, the filters will incorrectly fail to block a substantial amount of speech.  Thus, software filters have not completely eliminated the problems that public libraries have sought to address by using the filters, as evidenced by frequent instances of underblocking.  Nor is there any quantitative evidence of the relative effectiveness of filters and the alternatives to filters that are also intended to prevent patrons from accessing illegal content on the Internet.  Even more importantly (for this case), although software filters provide a relatively cheap and effective, albeit imperfect, means for public libraries to prevent patrons from accessing speech that falls within the filters’ category definitions, we find that commercially available filtering programs erroneously block a huge amount of speech that is protected by the First Amendment.  Any currently available filtering product that is reasonably effective in preventing users from accessing content within the filter’s category definitions will necessarily block countless thousands of Web pages, the content of which does not match the filtering company’s category definitions, much less the legal definitions of obscenity, child pornography, or harmful to minors.  Even Finnell, an expert witness for the defendants, found that between 6% and 15% of the blocked Web sites in the public libraries that he analyzed did not contain content that meets even the filtering products’ own definitions of sexually explicit content, let alone CIPA’s definitions.