Now with guess-your-search functionality!
The search box in Firefox has undergone a bit of renovation. When you start typing a search term in, it will provide a list of possible suggestions. For instance, if you use the Yahoo! search box and type "sha" you'll see a drop-down list that includes "radio shack," "shakira," "maria sharapova," and several other possible completions. The completions differ by search engine, and only the Answers.com, Google, and Yahoo! search boxes provide suggestions; if you're using the Wikipedia, Amazon.com, or Creative Commons search options, you won't see any.