An automated monitoring service downloads image files (including, e.g.,
graphic and video files) and audio files from various Internet sites, and
checks these files for the presence of embedded digital watermark data.
When found, such data is decoded and used to identify the proprietor of
each watermarked file. The proprietors are alerted to the results of the
monitoring operation, often apprising such proprietors of unknown
distribution of their image/video/audio properties.