Frode and his team at Liquid Information have launched a demo of Hyperwords. Hyperwords is a very big idea about tools that make the web a lot more linky and contextual. For now, the demo allows you to load a web page through Hyperwords and mouse over and select various functions from a menu including looking up the definition, searching for on search engines including Technorati and highlighting. The cool thing about the highlighting is that the info is added to the URL so you can copy paste the URL to someone to give them your highlighting. Anyway, I know Frode is looking for feedback so give it a try and let him know what you think.
UPDATE: Interview with Frode
UPDATE 2: Frode has released a new version: