Content-control software, content filtering software, secure web gateways, censorware, and web filtering software are terms for software designed and optimized for controlling what content is permitted to a reader, especially when it is used to restrict material delivered over the Internet via the Web, e-mail, or other means. Content-control software determines what content will be available or perhaps more often what content will be blocked.
The restrictions can be applied at various levels: a government can attempt to apply them nationwide (see Internet censorship), or they can, for example, be applied by an ISP to its clients, by an employer to its personnel, by a school to its students, by a library to its visitors, by a parent to a child's computer, or by an individual user to his or her own computer.
The motive is often to prevent persons from viewing content which the computer's owner(s) or other authorities may consider objectionable; when imposed without the consent of the user, content control can constitute censorship. Some content-control software includes time control functions that empowers parents to set the amount of time that child may spend accessing the Internet or playing games or other computer activities.
In some countries, such software is ubiquitous. In Cuba, if a computer user at a government controlled Internet cafe types certain words, the word processor or browser is automatically closed, and a "state security" warning is given.
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