Web content filtering—also known as Internet content filtering or simply content filtering—is a process wherein online materials are either allowed to pass or blocked altogether based on the examination of its actual content instead of its source or other related filtering criteria. This technique is most commonly used online to filter web access and email; it literally decides what a user can or cannot view according to how it's been configured.
Content filters typically make use of mail headers like the subject of a message, the information contained within the message body, or the overall content of a given email to classify, reject, or accept a message. The statistics-based Bayesian filter is incidentally the most popular type of content filter available. The term "content filter" is wide-ranging in the sense that certain anti-virus approaches can be considered as content filtering as well, since some of them scan abridged versions of either HTML content or the binary attachments of email messages.Parental control programs that examine data and then either restrict or change it (as with chat filtering) can also be considered as a content filter type as well.
Depending on where packets or contents are categorized in the Internet or OSI model, content filtering refers to innovations developed to determine the logic of data in order to sort out legitimate and benign material from malicious ones such as spyware, trojans, denial-of-service attacks, computer worms, viruses, spam, and so on. Data filtering technologies can also, to a certain extent, filter out content based on the application or chat subject matter, controversial email headers, swear words, hate website manifestos, shock sites, user requirements, and other similar categories.
Users should take note that the worldwide web lacks a clear, unambiguous safety model standard that will consistently restrain the continuing spread of security threats such as worms (malware that can theoretically overload the entirety of the Internet and caused a global-scale denial-of-service meltdown of network servers). Creating complex and intelligent content filters with the cooperation of the majority of ISPs and a definite security standard may be the best solution to this manmade online epidemic.