An all new feature of the Google Search Results for those users logged into their Google Gmail account. This feature allows you to dictate internally within your account how the results for particular key phrases are displayed. In other words you can effectively create your own personalised “top 10″ search results for keywords and phrases you search for regularly.
This wont affect rankings (yet) but I can see it having an effect once this gains momentum and popularity with users and may act as some kind of “vote” helping websites rank higher when more users have them personalised at the number one position within their own accounts, however I´m simply speculating about this at the moment!
For more detailed information about this check out the Official Google Blog here:
http://googleblog.blogspot.com/2008/11/searchwiki-make-search-your-own.html