Internet users can publish material that can reach millions of people at very low cost. This differs greatly from television and radio, which have a limited channel capacity and cede little control to viewers or listeners. Additionally, Internet users can control a great deal of the content they receive online. For example, Internet users can prevent their children from viewing certain material by employing inexpensive and easy-to-use technologies that can block or filter content based on the individual tastes and values of parents.