Child sexual abuse material, or CSAM, is imagery or video depicting the sexual abuse or exploitation of a child. Child protection organizations and industry use this term instead of 'child pornography' because it makes clear that the material is a record of abuse.

‍

‍Why it matters

This is a zero-tolerance category. Unlike most moderation, there's no policy judgment about whether to allow it, and it's illegal in nearly every jurisdiction. In the United States, providers who become aware of apparent CSAM are required by law (18 U.S.C. 2258A) to report it to the National Center for Missing & Exploited Children, or NCMEC, through its CyberTipline. Handling it correctly protects children, and it's also a legal obligation for the platform.

‍

‍How it's handled operationally

Reviewers don't copy, save, or forward suspected material. Cases go immediately through a dedicated escalation route to a specially trained team that handles preservation and reporting according to legal guidance. Because exposure is severe, teams working on this category need strict exposure limits and access to psychological support.

‍

‍How known material is detected

Most detection of previously identified material uses hash matching, where an image is converted to a fingerprint and compared against a database of fingerprints of known material. Microsoft's PhotoDNA is a widely used tool for this. New material that hasn't been seen before needs different tools, such as trained classifiers, followed by specialist human review.