Most of the libraries that use filtering software seek to
block sexually explicit speech. While most libraries include in
their physical collection copies of volumes such as The Joy of
Sex and The Joy of Gay Sex, which contain quite explicit
photographs and descriptions, filtering software blocks large
quantities of other, comparable information about health and
sexuality that adults and teenagers seek on the Web. One
teenager testified that the Internet access in a public library
was the only venue in which she could obtain information
important to her about her own sexuality. Another library patron
witness described using the Internet to research breast cancer
and reconstructive surgery for his mother who had breast surgery.
Even though some filtering programs contain exceptions for
health and education, the exceptions do not solve the problem of
overblocking constitutionally protected material. Moreover, as
we explain below, the filtering software on which the parties
presented evidence in this case overblocks not only information
relating to health and sexuality that might be mistaken for
pornography or erotica, but also vast numbers of Web pages and
sites that could not even arguably be construed as harmful or
inappropriate for adults or minors.


The Congress, sharing the concerns of many library boards,
enacted the Children's Internet Protection Act ("CIPA"), Pub. L.
No. 106-554, which makes the use of filters by a public library a
condition of its receipt of two kinds of subsidies that are
important (or even critical) to the budgets of many public