Content ID is YouTube’s automated copyright-matching system. Rights holders who own exclusive rights to a substantial body of original material that is frequently uploaded can supply reference files of their audio and video, and every new upload is scanned against that database. When a match is found, a Content ID claim is placed on the video and the owner’s chosen policy applies: block it, monetise it with ads, or simply track its viewing statistics. Policies can differ by country.
A claim is not the same as a copyright strike. Claims affect individual videos and usually not the channel, whereas strikes follow formal takedown requests. Uploaders who believe a claim is mistaken, for example because they hold a licence or the music is in the public domain, can dispute it, and YouTube can withdraw access from claimants who repeatedly make wrong claims.
For lo-fi channels and 24/7 streams, a wrong claim can redirect revenue or interrupt a broadcast, so keeping licences and documentation in order pays off. Disputes involving real rights questions may need professional advice.