Mainstream Loudoun et al. v. Board of Trustees of the Loudoun County Library et al.

The Loudoun decision was the first major court case challenging public library use of Internet filters. The decision in issuing a permanent injunction against the filtering policy supported unrestricted access to the Internet in public libraries. The Virginia library's policy was considered a form of prior restraint on the distribution of speech. Following the ruling, the Loudoun library board voted to allow adults unfiltered Internet access and parental permission slips for children to use unfiltered computers.

Though the Board was concerned that the Loudoun decision undercut the traditional role of librarians in deciding what materials a library should acquire, the court was clear that the decision only applied to the unique world of the Internet. In the realm of books, librarians continued to make acquisition choices. In the Internet world, all information is equally available at no additional cost with the click of a mouse.

Though the decision only applied to eastern Virginia, the effects were felt throughout the nation as libraries began to reassess their own policies toward Internet use. Left unanswered by the decision was whether it was constitutionally acceptable to use such filters on terminals set aside for children. The Loudoun decision reinforced the principle that minors hold fewer constitutionally protected rights than adults. Many public schools already required parental permission before allowing students access to the Internet on school computers.

Libraries also considered use of other measures, such as using privacy screens or optional filter by-pass codes. Another option was for public libraries to purchase some form of limited Internet access identifying only particular sites desired. The Internet served in the 1990s to test the constitutional notions of freedom of speech and press in ways that were previously unimaginable.