In Parker v. Yahoo! Inc., a US District Court dismissed in part an author’s copyright infringement lawsuit against Microsoft and Yahoo! for making a "cached" copy of his works available in their search results, because he had not taken steps to prevent the caching or have the content removed.

Parker had posted two of his publications on his website. He claimed that the search engines republished his works in their entirety without his permission when they made cached copies of his website available to their users. The search engines countered that Parker gave them an implied licence to display the content through his conduct.

The court found that Parker had known about, but failed to use, the search engines’ opt-out mechanisms, which would have prevented his site from being cached. (He could have followed the industry protocol of placing a robots.txt file on his web server, with instructions to the search engine crawler not to index or cache certain sections of his site.) He also admitted knowing that search engines honour take-down notices, and that he had never sent them a request.

Based on Parker’s silence and initial lack of objection, the court found that the search engines had an implied licence to display the works up to the filing of the lawsuit. It did note that commencing the lawsuit may have constituted a revocation of the implied licence. Since Microsoft and Yahoo! allegedly continued to display Parker’s works after that time, the court allowed Parker’s claim of direct copyright infringement to proceed for the subsequent period.