Yahoo replacing Google as Firefox 's default search engine, signaling new Yahoo ambitions

Yahoo may be getting more serious about search again.

Mozilla is dropping Google as the default search engine for its Firefox browser, replacing it with Yahoo for U.S. users on their computers, phones and tablets.

Yahoo had farmed its search engine out to Microsoft five years ago.

There have also been tensions between Mozilla and Google, with the search giant's Chrome browser stealing market share from Firefox for years.

Mozilla and Yahoo said in a statement Wednesday that they have agreed to a five-year partnership that is a "framework" for other possible product integrations and deals.