Launched in Nov. 2004, the browser currently boasts an estimated 45 million individual users, many of whom have already cycled through multiple iterations of the browser.
Based on open-source code, programs developed in a public community within which the underlying design of a software program is shared among developers, the application claims to be a more reliable alternative to Microsoft Corp.s dominant Internet Explorer browser.
Mozilla, a nonprofit organization focused on open-source efforts, credited the browsers following of avid users for spreading the word about Firefox and contributing a constant stream of updates to the application.
The group estimates that some 100,000 individuals have built, tested and promoted the software.
Some time later this fall, Mozilla promises to deliver Firefox 1.5.
"Our community of developers, testers, and grassroots marketers is rejuvenating Web browsing, which is why millions of new users make the jump to Firefox every week," said Asa Dotzler, liaison for the "Spread Firefox" effort, in a statement.
From the get-go, Firefox has promised to be more secure than Microsofts proprietary Explorer, and to offer users greater ability to customize the browser to suit their individual needs.
Firefox also is said to crash less frequently than Explorer, just as advocates of the open-source Linux operating system say their software is safer and more effective than Microsofts Windows.
However, despite the impressive download figure, at least one research group reports that usage of Firefox may actually be sliding. According to Janco Research, based in Park City, Utah, Firefox ranks second in the browser market with 8.8 percent of all users, while Explorer still commands 85 percent of all Web surfers.
Mozillas eponymous open-source browser ranked third in the study with 3.3 percent of the market, followed by America Online Inc.s software and Microsofts MSN, each of which accounts for less than 1 percent of all users.
Janco pointed to some security flaws discovered in Firefox earlier this year as one of the main reasons the browser may be losing steam.
"The positive glow on Firefox was dulled in April with the identification of some security gaps, and [the browser] seems to have lost its momentum," Victor Janulaitis, chief executive at Janco, said in a statement.
Jancos third-quarter browser market report stands in sharp contrast to its second quarter research which had predicted that Firefox could take over as much as 25 percent of the sector before the end of 2005.