Internet Filtering Can Create Unintended Roadblocks

August 6, 2003

Students and patrons who use school and library computers to access the Internet may be blocked from valuable information due to filtering software, warn observers, without a conscious decision by school officials or librarians to block such sites.

The Supreme Court recently upheld the federal law requiring pornography-blocking filters in schools and libraries that get federal funds. Internet filters are capable of blocking pornography without accidentally blocking topics such as breast cancer; however, filters are being set up to block an array of other content, from alcohol to bomb-building to sex education.

Some filtering vendors offer ''default'' configurations that block such categories as profanity, news and games as well as such intriguing catchalls as ''illegal/questionable'' and ''militancy/extremism.''

A review by the University of Michigan of 20 schools and libraries representing more than a half million students and 2.5 million library users found that just one had configured its filter to block pornography only.

While fewer than 1.5 percent of health sites are blocked by filters set to screen just pornography, 24 percent are blocked by those using additional categories, according to a Kaiser Family Foundation study, and as many as half of all sites on sensitive topics such as sexual health can be blocked.

Three out of four older teens have gone online to look for health information -- nearly half of them say they have been blocked from nonpornographic sites, according to another foundation survey.

Decisions about what types of content to block are based on software vendors' vague descriptions of options, say observers. Some categories are ill-defined (''gross'' or ''tasteless''), some well-intentioned but overly broad (''tobacco'' or ''violence''), and still others look like catchalls for those with an ideological agenda (''lifestyle'').