Headup is the latest company to attempt in-browser semantic search. The Firefox-only add-on that, surprisingly enough, uses Microsoft's Silverlight to do its heavy lifting, will scan whatever page you're on and search a cross section of the Web for related news stories, music, videos, and more.
To personalize the results it finds, you can plug in your contacts and accounts from various social services including Twitter and FriendFeed. This will pepper the results with related tidbits from them when applicable. For example, a quick Headup search for "cheeseburger" showed me that one of my FriendFeed buddies … Read more