Computers in Libraries Make Moral Judgments, Selectively
Monty Solomon
Smut in the stacks! What better conjures up the broken promises of
the Internet than the image of children sitting in a public library
downloading pornography?
Congress has made several attempts to control access to online porn,
most recently with the Children's Internet Protection Act, passed at
the end of 2000. The act required schools and libraries to install
software filters to screen out obscene sites as a condition for
receiving various federal subsidies.
Shortly after that, the American Library Association and the American
Civil Liberties Union sued to block the law's enforcement in public
libraries, arguing that the software isn't up to the task the law set
for it. In June 2002, a three-judge federal panel agreed. It
overturned the law, describing filtering technology as a "blunt
instrument" that not only fails to block many pornographic sites, but
also blocks a substantial amount of constitutionally protected
speech. Last week, the Supreme Court heard arguments in the
government's appeal of that decision.
I served as an expert witness for the library association in its suit,
on the basis of my background designing automatic text classification
systems, of which porn filters are merely a special case. In their
workings, filters are no different from the software that companies
use to automatically sort e-mail messages, a job they perform with
tolerable accuracy.
Tolerable, however, is a relative notion. We can live with the errors
that classification software make when its output is subsequently
reviewed by hand -- for example when the F.B.I. uses it to try to
locate potential child pornography sites. But human review isn't a
practical option in surveying the vastness of the Web. It has taken
the St. Louis Public Library 135 years to build its collection of 4.5
million holdings; the Web adds that many new documents every three
days. No software can identify a large portion of the pornography on
the Web without taking down a great many innocuous or useful sites on
the way.
In testing several filtering systems used by libraries, I found them
blocking access to everything from teenage sex advice sites posted by
Planned Parenthood and Rutgers University to a dollhouse furniture
site, Salon magazine and the home page of the Canadian Discovery
Channel.
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