SearchWiki lets users customize search by re-ranking, deleting, adding, and commenting on search results. With just a single click users can move the results they like to the top or add a new site. They can also write notes attached to a particular site and remove results that they don't feel belong.
These modifications will be shown to users every time they do the same search in the future. SearchWiki is available to signed-in Google users and the changes are stores in their Google Account.
The changes made only affect the user's own searches but one can see how the community has collectively edited the search results by clicking on the "See all notes for this SearchWiki" link.
For more in click here