In major shift, Firefox to use Yahoo search by default in US

Google's 10-year run as Firefox's default search engine is over. Yahoo wants more search traffic, and a deal with Mozilla will bring it.

In a major departure for both Mozilla and Yahoo, Firefox's default search engine is switching from Google to Yahoo in the United States.

'I'm thrilled to announce that we've entered into a five-year partnership with Mozilla to make Yahoo the default search experience on Firefox across mobile and desktop,' Yahoo Chief Executive Marissa Mayer said in a blog post Wednesday. 'This is the most significant partnership for Yahoo in five years.'

The change will come to Firefox users in the US in December, and later Yahoo will bring that new 'clean, modern and immersive search experience' to all Yahoo search users. In another part of the deal, Yahoo will support the Do Not Track technology for Firefox users, meaning that it will respect users' preferences not to be tracked for advertising purposes.

With millions of users who perform about 100 billion searches a year, Firefox is a major source of the search traffic that's Google's bread and butter. Some of those searches produce search ads, and Mozilla has been funded primarily from a portion of that revenue that Google shares. In 2012, the most recent year for which figures are available, that search revenue brought in the lion's share of Mozilla's $311 million in revenue.

Google now has Chrome, though, and it doesn't have to share search-ad revenue from that browser with anybody but itself. Yahoo, meanwhile, has ambitions to reclaim its former prominence in Web search.

'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,' Mayer said. '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.'

Search volume is important to search engines. The more that people search, the more opportunities advertisers have to show ads, including ads associated with search terms that might not otherwise be common enough.

Terms of the deal weren't announced. Firefox users will continue to be able to change their default search engine, though.

Firefox was an early leader in building a search box directly into the browser, but after a decade sending traffic to Google, Mozilla concluded it was time for a change.

'Google has been the Firefox global search default since 2004. Our agreement came up for renewal this year, and we took this as an opportunity to review our competitive strategy and explore our options,' the organization said.

Mozilla has toyed with search-engine changes before, for example with a dalliance with Yandex in Russia, by setting Baidu as the default search engine in China and by making Bing, from erstwhile rival Microsoft, another option.

The new deal with Yahoo is only one change in which Mozilla will become more locally flexible, the non-profit organization said. Mozilla is keeping Baidu in China and switching back to Yandex in Russia.