Yahoo Inc struck a deal with Firefox maker Mozilla Corp to replace Google Inc as the default search engine on the Firefox Web browser in the United States, a move that Yahoo Chief Executive Marissa Mayer said will help boost its flagging search market share.
i don't think Google need to move because the first thing people will search when they see Yahoo is "Google"
The Mozilla deal means that users of the Firefox browser in the U.S. will automatically be routed to search results on Yahoo’s website when they type a query into the small box that appears at the top of the browser.
No need as it only effects the small search box that appears at the top of the browser.
I set it to ddg on my mobile and desktop Firefox. I never really got the big deal about what was default, but a large # of people just leave the default and wonder why googling something searches yahoo (or bing or or or) now