Content Management, Filtering and the World Wide Web


Filtering is Not Censorship

The fact that pornography on the Internet is both ubiquitous and unavoidable and that students may access it -- from school, at home, from the library, with friends, etc. -- suggests only that we as parents, teachers and community members must be aware of the risks and consequences. Most importantly, we should understand the difference between censorship and filtering.

The Merriam-Webster Dictionary ( defines 'censor' as 'an official who examines materials for objectionable matter; an official (as in time of war) who reads and deletes material considered sensitive or harmful.' Censorship is an act of government that, by definition, precludes free choice. The US constitution guarantees free speech, and thus restricts government censorship dramatically. Censorship at other times is a violation of our civil rights.

Parents and teachers filter students and kids' exposure to all sorts of things all the time. We monitor their playmates and don't let them talk to strangers. We are encouraged to monitor and control what shows they watch on TV, the songs they listen to on the radio and the books they read. This is to a very great degree what good parenting is all about.

Schools act in 'loco parentis' when teaching children and so standards of health and safety that apply to parents apply generally to teachers. Just as importantly, teachers teach by providing students with information and accompanying analysis. The whole notion of a scope and sequence suggests that as teachers we take responsibility for determining the information content of a child's education. By teaching them arithmetic before we teach them calculus we filter their exposure to mathematical information.

Acceptable Use Policies

Many schools are adopting 'Acceptable Use Policies' -- documents that describe how the Internet is to be used in school and the consequences for its misuse. To be most effective, acceptable use policies should be based on a thorough analysis of student needs for information and protection. Schools should post their policies on their Web sites, send them home to parents and teach them to students. Some schools require students to sign the Acceptable Use Policy, often before granting free Internet access. Schools should consider linking their Acceptable Use Policies to any filtering technology they employ. Fortunately, there are multiple technologies available to help monitor and enforce acceptable use policies, so policies can be enforced in a flexible way that accommodates the needs of different schools and different students.

Monitoring Web Usage

Standard browser and server technology can guide our students to appropriate content while helping us stay involved and aware of what they are doing. All browsers include a 'history' file that lists the time and date of every Web site accessed. Web proxy servers also provide a history or audit of sites accessed for all of the machines served. Some proxy servers include powerful reporting tools as well. These tools are basic to school use of the Web. However, monitoring alone can only be reactive, identifying problems after they happen. For proactive control, additional content filtering technology is necessary.


Filtering Technology

Filtering Technologies fall into three general types -- list-based URL filtering, text filtering, and content recognition technology.

List-Based Filtering

URL filtering, the most commonly used technology, is a database of 'unacceptable' Web sites and domains. These lists are frequently categorized by type of content. Categories include obscenity, sexual content, alternative lifestyles, illegal activity, drugs, violence, hate speech and crimes, sports and various forms of leisure.

List-based filtering has two weaknesses. First, it is costly. The lists must be updated frequently, and users must pay ongoing subscription fees. Second, and more important, vendors' ability to maintain their lists is being outstripped by current Web growth. Some analysts estimate that a new Web site is added an average of every 18 seconds. List-based technology cannot possible keep up.

A more restrictive alternative to 'prohibited site' lists is to only allow student browsers to go to certain Web sites -- 'virtual playgrounds' that are trusted to provide content appropriate to students and children. There are a variety of tools available that can 'tune' the browser to a trusted site or virtual playground. This kind of filtering has the advantage of restricting students to appropriate content while providing the safest access, and may be entirely appropriate for very young students.

Text Filters

Web content can also be managed through the use of 'text filters.' Text filtering technology limits the words that can be displayed in the browser and can be used to block pages containing inappropriate content. Unfortunately, simple text filters have trouble distinguishing appropriate uses of the same word from inappropriate uses. Thus, filtering solutions relying on text filters often block pages that students and teachers need or want to access.

Content Recognition

Recently, a new class of filtering technology has been developed that employs neural networks and other artificial intelligence to reduce the dependence on human reviewers and to provide more sophisticated content screening than simple text filtering. Content recognition technology uses trained neural networks to identify patterns on incoming Web pages and to permit or block the page. For example, when content recognition tools encounter the word 'breast' they will check the context and structure for words such as 'mammogram.' Students will be allowed to see the medical information, while a pornographic site will be blocked. By dynamically evaluating Web content in real time, content recognition technology is always current and avoids the costs and limitations of list-based filtering.

Instructional Management and Content Filtering

Instructional management and filtering is the most proactive approach to creating a positive Web experience for students. Through a combination of teacher direction, browser technology, Web servers and directories, and filtering technologies, teachers can direct the student to subject-specific Web locations. For example, science teachers can direct students to the Eisenhower National Clearinghouse (, math teachers can direct students to the Math Forum (, and language arts teachers can direct students to the English Server (

'Safe' search engines and directories can be employed to avoid inadvertent access to inappropriate material. Teachers can extend and enrich the Web as an educational experience using information sources such as EBSCO and Proquest, or unique Web-based excursions such as ThinkQuest and MayaQuest. Web activities and materials such as the Scholastic Network or CCCNet can provide valuable supplements to standard information sources.

Bookmarks and Favorites Help Students Find What They Want

Helping students find what they want -- quickly and easily -- may be the most effective form of filtering. The easiest way to find something on the Internet is via a bookmark or favorite file. Search engines are notorious for providing too much information, and students may not know how to access the most useful subject directories.

School browsers should be set with well-organized bookmark/favorite files and students should be trained in their use. History file bookmarks can be edited and organized, saved, searched, sorted and cleared. Because bookmarking is so much a part of effective surfing, schools should consider creating and securing standard bookmark sets for all students or groups of students and 'personal' bookmarks for individual students.

Privacy Protection

Students in schools share computers. In a given period of time, 25 to 250 students may have access to the same computer and the same browser. As a consequence, students are subject to loss of privacy in a variety of ways. The same tools in the browser (caching, history file, bookmark file) that make filtering and focusing possible also reveal private information. The browser's history file contains all the Web sites accessed -- regardless of who accessed them. Thus it is easy to 'snoop' to determine where other users are surfing.

Student privacy can be violated through chat rooms or through routine Web site access. Web sites regularly collect data about their users. Standard server technology provides basic information about all Web site visitors: e-mail addresses, the operating system of your computer, and whether you accessed the site from an online service, an Internet access provider, an educational institution or a business. All of this information could be useful to potential abusers or unwanted solicitors. To combat this double threat, schools can use content filtering and cookie management to keep students from intentionally or unwittingly transmitting personal information over the Web.

Cookie Management

Many Web sites maintain user privileges (such as e-mail accounts) through the use of 'cookies' -- digital markers employed by Web servers to maintain users' information as they surf through the site. If a student leaves his or her computer without quitting the browser, the cookie file will be maintained and the next student to sit down at the computer may have access to whatever private accounts have been opened. Persistent cookies of this type are risks to student privacy on school computers. Browser options and preferences provide some support for 'cookie management.' Both standard browsers provide the ability to decline cookies and to notify users before accepting cookies. The latest version of Navigator also supports a feature that accepts only cookies that get sent back to the originating server. The best solution is to associate cookies with individual users and browser sessions -- thereby supporting site access while avoiding the privacy pitfalls.

Outgoing Content Filtering

Outbound content that users voluntarily submit in e-mail, chat room forums and server-based forms may be the most dangerous and difficult risks to manage for students using the Web. Text filtering or content recognition technology can be used to block users from sending out personal information such as name, age or address and chat rooms can be blocked. But these technologies can only be partially effective and in many cases may have the effect of blocking student access to desired sites and information.


Filtering designed to give students free access to the entire Web is the least restrictive way to keep students from adult or inappropriate content. But this technology is only as good as the filtering criteria and technology. Filtering solutions should combine the best of the available technologies -- real time dynamic content recognition, and 'virtual playgrounds' combined with list and text based filtering.

In approaching the new realities the Internet is creating, we must stay involved and become informed. In short, we need to talk with our kids about the Internet. We need to surf and search with them. We need to create rules that we feel comfortable with at home and policies that are responsive at school. The new technology of the Internet may have changed the pace of the problem, but it has not created the problem. Just as technology didn't create the problem we must not rely solely on technology to 'fix' the problem.

As a vast global storehouse of information, the World Wide Web offers a rich learning opportunity to educators and students. To take full advantage of this learning opportunity, we must manage its risks to create a safe yet open learning environment. New technologies and information sources hold the potential to significantly improve how we use the Web to teach and learn.



Rich Chapin is co-founder of SmartStuff Software ( SmartStuff's software products include FoolProof Security, FoolProof Network Administrator and FoolProof InterNet. Before founding SmartStuff, Rich taught for twenty years in kindergarten through college. He can be reached at [email protected].

Acceptable Use Policy Links

Safe Surfing Tools --
NMCTE Selected Acceptable Use Policy Resources --
School Librarian Links -- www.nyx.Net/~rbarry/aup.html
Acceptable Use Policies -- A Handbook --'E/Technology/AUP/home.shtml
Acceptable Use Policies --
Acceptable Use Policies --


Privacy on the Web

How Information is gathered --
Web Privacy Protections and Considerations for Students Privacy on the Web --

Filtering -- Censorship Debate & Issues

FamilyEducation Forums -- America Links Up
The Cyberporn Debate --
Sex, Censorship, and the Web --
Censorship, Freedom of Speech and Child Safety on the Web --

This article originally appeared in the 09/01/1999 issue of THE Journal.