The US Patent and Trademark office granted Google a patent for "systems and methods for highlighting search results". According to the description, the patent covers the interception of web documents, that were retrieved as links in a search query by a user or system. Google then "highlights one or more occurrences of the search term in the intercepted web document."
The patent application was submitted on Dec. 13, 2000 and confirmed on January 4, 2005. (THG)