With its online chat feature, Mozilla works to break down the walls around services like Microsoft Skype and Google Hangouts.
Microsoft's browser was the dominant force in 2009 when the EU required the company to offer consumers a choice of browsers. But that has changed dramatically over the past several years.
In Windows 10, Microsoft's browsers -- both IE and Spartan -- will get the tech Firefox uses to speed up Web-based games. And that's a challenge to Windows itself.
Johnathan Nightingale, Mozilla's vice president of Firefox, is leaving. Firefox is stronger now after a tough 2014, he says, but his departure means more unsettled times for the browser maker.
In a major reversal, Firefox's leader tells Mozilla community members he wants the open-source browser on Apple's mobile devices. A better mobile presence is key for Firefox's future.
The newest competitor to Internet Explorer comes from Microsoft itself. Project Spartan is the company's take on browsing in Windows 10.
A partnership with Verizon and other carriers is aimed at bringing the browser-based operating system to wealthy countries. But don't expect ordinary slab-of-glass phones.
Mozilla says the new Firefox ad initiative takes a kinder, gentler approach to pitching you products.
Previously thought limited to Apple and Google browsers, the flaw leaves communications between affected users and websites open to interception.
Firefox got its first boost when Web programmers flocked to it a decade ago. Now Mozilla is trying that strategy afresh with a coder-focused version of the browser.