Ubiquity is a Firefox Add-on that enhances the browser by adding a range of functions that can be invoked by natural language commands. Ubiquity envisions a new concept of user-centric browsing as opposed to site-centric browsing. I think of it as a promising tool to reduce amount of open tabs needed when browsing. Read more about the concept and its goals here.
I played around a little and created a (rather modest) davindi command that looks up stuff in the Kennisnet Foundation search engine Davindi. If you have Ubiquity installed you should be able to add the command here.