Earlier on this year Ubuntu made a short-lived switch to Yahoo! as the default search engine in Firefox.
This was soon redressed based on ‘user experience, user preferences, and costs and benefits for Ubuntu and the browsers and other projects that make up Ubuntu.’
Yahoo!-ites who would rather use the official Ubuntu start page with Yahoo! still can – just head to start.ubuntu.com/10.04/Yahoo/ and set it as your home page.
Thanks to mehd36