Yahoo has replaced Google as the default search engine for Firefox in the United States, after Mozilla Corp set a 5-year deal in stone in a move which Yahoo will no doubt be hoping could lead to the start of inroads being made into the disproportionate search market share Google has enjoyed for eons now.

It brings to an end a 10-year arrangement between Mozilla and Google, and when 2012’s profits data is considered, which shows Google accounting for 90% of Mozilla’s $311m revenue, the radicalness of the move is plain to see.

Firefox users in the US will now be re-directed to Yahoo’s search results when they enter a query into the search box, organically providing Yahoo with enhanced coverage in the country with the second largest internet population after China.

As such, Marissa Mayer, chief executive of Yahoo, has stated her expectation for Yahoo to make gains in search market share whilst keeping her cards close to her chest regarding the financial ins and outs of the deal. Any gains would be most welcome in light of Yahoo’s record low search market share in June of under 10%, and given Mozilla’s claim that over 100 billion searches are conducted on a yearly basis through Firefox, this deal could prove to be an immensely lucrative one.

Mayer also hopes that Yahoo can build on their relationship with Microsoft, following on from the mutual promotional deal struck in 2010 between the two online giants both seeking to provide greater competition to the overarching search mammoth that is Google.

Meyer said: “I think that if you look at the overall search space, in Yahoo’s case, we’ve been trading share with our partner Microsoft for some time.

That said, the whole thesis about partnership is that we wanted to ultimately gain search share against the broader ecosystem. It hasn’t really accomplished that.

I think, however, this partnership does allow ideally Yahoo to grow its share and hopefully the collective search alliance to grow its share.”

With Yahoo continuing to flounder in Google’s wake with the latter consuming over 90% of the online search market, and Firefox trailing behind Google’s increasingly popular Chrome browser, the deal also indicates another partnership underpinned by a desire to reduce the far-reaching influence of Google.

Such influence could only have grown greater if Google had actively sought to outbid Yahoo for Firefox’s continued service, however given Firefox’s lack of a mobile presence in an increasingly ‘tablet-orientated’ world and Chrome’s exponentially increasing default presence, the decision appears justified.

The reality is Firefox needs to buck up its ideas otherwise it will find its relevancy questioned by all major online powers in the years to come, regardless of how many desktop searches it currently produces.

Google chairman, Eric Schmidt’s asserted last month that Amazon were Google’s primary rival in online search, Yahoo will be hoping to make him eat his words over the course of the next year, but it is hard to see how much more Firefox value offers other than a short-term image boost.