Censorware is a term used pejoratively to describe software that philtres out undesirable Web sites or content. Examples include Cybersitter, N2H2, Netnanny, Surfwatch, and Wisechoice. This kind of software is designed to restrict an individual's ability to send or receive certain types of information, and for that reason its use (in public libraries, for example) is a contentious issue. organisations such as the American Civil Liberties Union (ACLU) and the Electronic Privacy Information centre (EPIC) argue that the use of censorware conflicts with individual rights to freedom of expression and freedom of association, as mandated by the United States constitution.