Search Cloud is a search engine that uses weighted keywords to determine relevancy in its results. When entering search terms you can change which words or phrases need priority over others by changing their size from one to five. More important keywords appear larger, and will be bolded in the results.
The application runs entirely in Adobe Flash, and while not nearly as fast as Google, is no slouch. I was able to find some highly targeted results with just three or four keywords which ended up being better than Google and Yahoo's in several cases. To open results you'll need to double click them, which is a little odd. You can also go back and revise your search by deleting keywords one by one or changing what size they are.
Below is a demo video of how to set up a search with the tool, although I recommend giving it a look yourself to get the feel of re-sizing your keywords.