On Internet websites that invite users to post comments, content moderation is the process of detecting contributions that are irrelevant, obscene, illegal, harmful, or insulting, in contrast to useful or informative contributions, frequently for censorship or suppression of opposing viewpoints. The purpose of content moderation is to remove or apply a warning label to problematic content or allow users to block and filter content themselves.
Various types of Internet sites permit user-generated content such as comments, including Internet forums, blogs, and news sites powered by scripts such as phpBB, a Wiki, or PHP-Nuke. and etc. Depending on the site's content and intended audience, the site's administrators will decide what kinds of user comments are appropriate, then delegate the responsibility of sifting through comments to lesser moderators. Most often, they will attempt to eliminate trolling, spamming, or flaming, although this varies widely from site to site.
Major platforms use a combination of algorithmic tools, user reporting and human review. Social media sites may also employ content moderators to manually inspect or remove content flagged for hate speech or other objectionable content. Other content issues include revenge porn, graphic content, child abuse material and propaganda. Some websites must also make their content hospitable to advertisements.
Also known as unilateral moderation, this kind of moderation system is often seen on Internet forums. A group of people are chosen by the site's administrators (usually on a long-term basis) to act as delegates, enforcing the community rules on their behalf. These moderators are given special privileges to delete or edit others' contributions and/or exclude people based on their e-mail address or IP address, and generally attempt to remove negative contributions throughout the community. They act as an invisible backbone, underpinning the social web in a crucial but undervalued role.
As of 2017, Facebook had increased the number of content moderators from 4,500 to 7,500 in 2017 due to legal and other controversies.