Block every site until you identify it as an approved site. Require regular updating, since thousands of new sites are added daily. Cannot distinguish the context in which a word is used. This filters out useful sites. Internet filters do not always work as advertised.
Testing shows that all Internet filters fail to block some sexually explicit sites.
Filters cannot adapt to the age and level of maturity of a particular child. Filters do not help your child learn to make independent judgments and to say no. Choices of words, ideas, and topics to be blocked are driven by the product owner's personal values, ideology, and political agenda. These factors may exclude sites that have information regarding sex education, environmentalism, homosexuality, abortion, or other health-related issues such as breast cancer, among others. Your library provides access to the widest possible variety of resources that meet the needs of all members of society.