Google is considering allowing users of its search engine to tinker with query results by re-ranking them and commenting on them.
The company has already run public tests on its search-results pages that contain up and down arrows next to listed links, as well as buttons that allow users to append comments to results. Read the full article
have a look too at the experimental search in their labs - also very interesting with things like timelines, map view and others. See here: http://www.google.com/experimental/