Firefox's default search engine is Yahoo, which replaced Google

Mozilla and Yahoo have announced a new "strategic five-year partnership that makes Yahoo the default search experience for Firefox in the United States on mobile and desktop", with the companies adding they will explore other potential "future product integrations and distribution opportunities to other markets".

Until now, Google was the default search engine in Firefox, Mozilla's popular web browser, which will be replaced with Yahoo. There was a time when Firefox was the biggest competitor to Microsoft's Internet Explorer, but now Google is the competitor with Chrome. Firefox has around 16% of the browser market in the US according to StatCounter.

Yahoo CEO Marissa Mayer took to the company blog, talking about the new partnership: "At Yahoo, we believe deeply in search - it's an area of investment and opportunity for us. It's also a key growth area for us - we've now seen 11 consecutive quarters of growth in our search revenue on an ex-TAC basis. This partnership helps to expand our reach in search and gives us an opportunity to work even more closely with Mozilla to find ways to innovate in search, communications, and digital content. I'm also excited about the long-term framework we developed with Mozilla for future product integrations and expansion into international markets".

Firefox will bake Yahoo in as the default search engine in December, with Mayer adding that it will feature "a clean, modern and immersive design that reflects input from the Mozilla team".