Signature analysis of streamed download data narrows a list of likely candidates after a search engine search has been performed. "Streamed download" means that the data is brought byte by byte to the searcher's computer and then discarded. During the streaming process the subject data, in binary form, is parsed into segments and each segment is provided with a signature based on the content of the segment. The signatures of the individual segments are then compared to signatures of the material that may have been infringed. If there are no matches, the streamed download data is discarded. If there are enough matches of the signatures, the offending data is displayed for visual inspection. Only caching and display takes place if a potential infringing segment is discovered.