What Is a Supplemental Result?
Web sites would be marked as supplemental results by Google if the search engine noticed that the page hadn’t been accessed in a long time or if it had duplicate content. Supplemental results won’t show up in normal search rankings and instead appear within its supplemental index and only appear in search results if Google couldn’t find results within its main index. Google announced that it would stop using the supplemental results index in 2007.
Get Found. Naturally.