Friday, April 4th was 404 Day - a day meant to call attention to Internet censorship in public schools and libraries in the United States. This censorship is the result of a well-meaning but misguided law, the Children's Internet Protection Act (CIPA), which ties federal funding for public schools and libraries to requirements to filter child pornography and content that is obscene or "harmful to minors." Unfortunately, bad and secretive filtering technology and over-aggressive filtering implementations result in the filtering of constitutionally-protected speech, among other problems.

The day centered around a digital teach-in for an in-depth discussion of the issues, featuring: Deborah Caldwell-Stone, Director of Intellectual Freedom at the American Library Association; Chris Peterson from MIT's Center for Civic Media and the National Coalition Against Censorship; and Sarah Houghton, blogger and Director of the San Rafael Public Library in Northern California.

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They addressed such issues as the cost and efficacy of these filters, the lack of transparency around what is filtered, and how you can ask your librarian to turn them off. The video, above, is a fantastic resource for beginning to understand problems CIPA creates.

Concurrently, a discussion ranged on Twitter around the hashtag #404day, as users, including Senator Ron Wyden, asked questions and shared their own experiences with filtering software in libraries and schools.

Many of those participating in the online discussion discussed the futility of filtering and how they had learned to circumvent filters at early ages, and brought up how the filters disproportionately affect low-income communities or those who rely on public computer access.

When the screen reads “404 Error – Not Found” we need to recognize that one of the things which is not being found is the values of libraries.

Throughout the day, librarians, researchers, teachers, and even a student blogged about how CIPA hinders their work, stifles speech, and runs counter to the ideals of public libraries. From an explainer about the censorship reporting tool Herdict to the experiences of a researcher unable to access material she needed to the manifesto of high school librarian preferring trust and education to blocking, the posts illustrated the personal and social harms of censorship under CIPA.

We're thrilled about the discussion the day engendered and thankful to our partners at the National Coalition Against Censorship and the Center for Civic Media at MIT, the teach-in participants, and all those who joined in blogging or tweeting throughout the day. The next time you get a 404 error at the library, we hope you think about why it's there. Ask your librarian whether it's because of filtering and to turn the filtering off if it is.