Filtering technology, while making progress in its ability to recognize inappropriate materials, still has significant drawbacks that make the cure potentially worse than the disease.
Filters use three primary approaches to inappropriate material, and each has pedagogical problems.
The majority of filters use a blocking approach. These programs maintain long lists of sites deemed unsuitable for children. It's true that material that's appropriate for high school students may not be appropriate for primary students. Lists of blocked sites, however, may not recognize the age of the searcher. Another problem with this type of blocking is the agenda of those who develop the lists of inappropriate sites.