"Having converted quite a few people to the world of GNU/Linux,
I am often asked by parents, 'Can I set up parental Web filters for
my children using Linux?' The answer is yes, and here's how.
"A Web filter is a software that can filter the type of content
a Web browser displays. The filter checks the content of a Web page
against a set of rules and replaces any unwanted content with an
alternative Web page, usually an 'Access Denied' page. The type of
content to be filtered is usually controlled by a systems
administrator or a parent..."