Yahoo currently owns about 10% of the U.S. While Firefox usage has declined over the last few years, it still accounts for at least 15% of the U.S. This partnership with Firefox will surely give Yahoo - and Microsoft - a stronger presence in the search market, however. There have long been rumors that Yahoo could end this deal and bring back its own search engine, but that seems unlikely given the investment the company would have to make after it dismantled its old search engine infrastructure. Yahoo Search, in its current form, is powered by Microsoft Bing, of course, though the company heavily modifies the results it gets from Microsoft, both in terms of layout and ranking.

This partnership helps to expand our reach in search and also gives us an opportunity to work closely with Mozilla to find ways to innovate more broadly in search, communications, and digital content.” Likewise, Yahoo’s CEO Marissa Mayer today noted that she believes that “search is an area of investment, opportunity and growth for us. featuring the best of the Web, and to explore new innovative search and content experiences together.” “We are excited to partner with Yahoo to bring a new, re-imagined Yahoo search experience to Firefox users in the U.S. Our agreement came up for renewal this year, and we took this as an opportunity to review our competitive strategy and explore our options,” said Chris Beard, Mozilla’s CEO in a statement today. “Google has been the Firefox global search default since 2004. That contract with Google was set to expire this year, though, and it look like either Yahoo made an offer Mozilla couldn’t refuse or Google decided to walk away from the deal.

Indeed, in 2012 - the last year we have data from - 88% of Mozilla’s income came from Google. The Mozilla Foundation has long made most of its money through its search partnership with Google, which has always been the default in Firefox. Google, DuckDuckGo and a number of other local search engines will remain as built-in alternatives. In Russia, Mozilla will use Yandex Search and in China, it will use Baidu as the default. The new search experience will feature “a clean, modern and immersive design that reflects input from the Mozilla team.” Here is what that will look like:

As a part of this five-year deal, Yahoo will also launch a new search experience for Firefox users in the U.S., which should go live at the same time Firefox makes the switch away from Google. Starting in December, Firefox will use Yahoo as its default search engine in the United States on mobile and desktop.

Mozilla firefox search default engine