Arguably, the Internet poses a much greater risk of damage to children than do television, movies, or music. That's because the major media are at least identifiable and subject to some pressure and legislation.
Even though many companies that provide Internet access seek to provide subscribers with safe experiences, it's not possible to monitor everyone. And the online world, like the rest of society, includes some people who may be hateful, obnoxious, or even exploitative. As a result, children can be targets of crime and harassment on the web, and thus need parental supervision and common-sense advice.
Understand that no plan or program is perfect. For instance, even if software does effectively block what you believe your children shouldn't see, it may not block what the child may say, such as giving out an address or agreeing to meet with a stranger. There’s no substitute for parental involvement, so the best approach is to use a combination of technology and informed supervision.