If you're referring to the way, e.g. Youtube, automatically detects the author of the video or artist upon upload, then this article will give you an overview a

If you're referring to the way, e.g. Youtube, automatically detects the author of the video or artist upon upload, then this article will give you an overview about tagging "audio": http://en.wikipedia.org/wiki/Acoustic_fingerprint http://en.wikipedia.org/wiki/Acoustic_fingerprint