The new feature, Preferred Sites, increases custom search results by allowing users to create a list of sources that show up higher in search query results. The tool suggests frequently visited sites based on search history.
Similar to SearchWiki, the new feature affects searchers only when they sign into their Google account. SearchWiki allows users to reorganize search results. The Preferred Sites feature gives users another option to customize their search results. The combined features bring Google's custom search engines to more users.--Laurie Sullivan