See http://www.eff.org/deeplinks/2007/07/harry-potter-and-digital-fingerprints http://www.eff.org/deeplinks/2007/07/harry-potter-and-digita... and search for "R

See http://www.eff.org/deeplinks/2007/07/harry-potter-and-digital-fingerprints http://www.eff.org/deeplinks/2007/07/harry-potter-and-digita... and search for "Recorder Identification Code". I don't know if there's a way to subvert this.