This news is a few weeks old but I was pleasantly surprised to hear that a Firefox add-on, built by a team called kekeke, was the winner of the 2008 Yahoo! Kimo (Taiwan) Open Hack Day. If anyone has any more information about the team who won, or the add-on that was developed, please leave a comment.
The winners, kekeke, wrote a Firefox extension which allows users to select any keyword on any website and receive a summary of several Yahoo API search results (Flickr, Map, Knowlege Plus, and Lifestyle), without opening a new browser window. More relevant results will display in a stronger colour and users can save for later, or share results with friends.