The browser, based on the Mozilla Foundation's open-source development work, was made available for free download early Tuesday.
Firefox 1.0 isn't significantly different from the preview releases launched in recent months. Mozilla changed its default start page to appeal to new users, but other changes involve minor performance improvements and bug fixes.
The release could nonetheless have a big effect if prerelease trends propel the open-source browser into serious contention with Microsoft's Internet Explorer.
And the Mozilla Foundation is already cooking up its next moves to challenge IE's dominance. Now that it has the Firefox 1.0 milestone under its belt, the foundation has identified three areas for future growth and development: cell phone and small-device browsing, desktop search integration, and OEM (original equipment manufacturer) distribution.
"It's been a tremendous year, and we can't see anything but upside the way things are heading right now," said Chris Hofmann, the Mozilla Foundation's director of engineering. "We're just starting the planning for the initiatives that are going to be important in the coming year."
But Microsoft says it doesn't feel threatened by Firefox. Just days after the launch of Firefox 1.0, Microsoft executives defended IE, saying it's no less secure than other browsers and doesn't lack any important features.
At a security roundtable discussion in Sydney, Australia, on Thursday, Ben English, Microsoft's security and management product manager, told attendees that IE undergoes "rigorous code reviews."
"Because IE is ubiquitous, you hear a lot more about it, but I don't think that Internet Explorer is any less secure than any other browser out there," English said.