Search Cloudlet is a light-weight, simple to use Firefox extension, which energizes Google and Yahoo searches by adding a tag-cloud to them, there-by helping you to refine your search resulting in more accurate results.
You can adjust the number of keyword tags you want to see below the search box and it automatically re-searches as you click and add them. Search Cloudlet works by looking at the words, sources, locations and other data in the search results to create a weighted tag cloud — the bigger the term the more frequently it pops up in the results.
Perhaps the most surprising thing about Search Cloudlet is that didn’t seem to add any overhead to the page load time. In my testing both Google and Yahoo loaded just as fast with Search Cloudlet installed as without. In addition to standard Google and Yahoo searches the extension works on Google News both for keywords and locations. It also works for Google Blog search in a really neat way by adding tags for each author that you can click on to filter which posts come up.