Google has launched “SearchWiki,” a way for you to customize search by re-ranking, deleting, adding, and commenting on search results. With just a single click you can move the results you like to the top or add a new site. You can also write notes attached to a particular site and remove results that you don't feel belong. These modifications will be shown to you every time you do the same search in the future.
SearchWiki should be available automatically if you are logged in to a Google account. The changes you make are stored in your Google Account and make only affect your own searches. But SearchWiki also is a great way to share your insights with other searchers. You can see how the community has collectively edited the search results by clicking on the "See all notes for this SearchWiki" link.
Watch demo video for a few ways to use SearchWiki in this short video: