Tapping once again into the collective talents of the open-source community, the new Firefox 2.0 Web browser is unambiguously a success.

Released late Tuesday, the Mozilla Foundation's latest Net-surfing tool is almost everything Web denizens have come to expect from the popular Internet Explorer alternative. Firefox 2.0 offers a handful of obvious improvements in searching and security and a couple of new features, and it largely keeps doing well what it has done well before.

This said, it breaks little genuinely new ground.

That's not a criticism, particularly given that the Web has long since become as mainstream as microwave ovens. Indeed, developers say their goal for the new browser was decidedly evolutionary, despite high hopes for a few advanced features that didn't make the final cut.

"We wanted to continue the evolution that started with Firefox 1.0," says Mike Beltzner, the Mozilla Foundation's "phenomenologist." "We wanted to make sure users still have full control over the browser and the full ability to customize it, and make sure they can actually understand those options."

This continued focus on simplicity and extensibility makes Firefox 2.0 an extremely solid product, with a few flashes of brilliance. It's suitable for anyone from novice Web surfers to hard-core coders. But this time around, its pathway into the market isn't quite as clear.

When the browser's 1.0 version was released almost exactly two years ago, it had the new-browser market almost to itself. Microsoft's last major IE update was three years old--an eternity in Internet time. Meanwhile, smaller rivals such as Opera Software had released technologically more-advanced products but had failed to gain significant traction, while IE itself had been dogged by persistent security flaws.

All of this contributed to the explosive interest in Firefox. Within a year, some analysts estimated that Mozilla's browser had captured a 10 percent market share, with far higher estimates in some tech-savvy subgroups.

This time the competition is stiffer. Just last week, Microsoft released its own long-awaited IE 7.0, adopting the tabbed-browsing and built-in search features that have been Firefox's trademark. It lacks some of Firefox 2.0's advanced features but adds a few new bells and whistles of its own, such as a handy thumbnail view of all open tabs.

By contrast, the new version of Firefox looks considerably more like its immediate predecessor. Users will find that the interface has been given a slight face-lift, but the familiar customizable search bar, toolbars, and buttons remain in place.

The tabbed-navigation system as been updated, however. Each tab now has its own "close" button, and a separate drop down lists all open tabs. Tabs accidentally closed can be restored, with content such as e-mail drafts or downloads in progress intact. As before, groups of several tabs, holding separate Web pages, can be launched simultaneously on start up in place of a single home page.

Two specific improvements are likely to be most popular among the Web 2.0 and power-surfer crowds.

In the thank-god-somebody-thought-of-it category comes an automatic spell-check feature that scans Web fields such as e-mail messages, blog posts, and comment boxes. As in traditional word processors, spelling mistakes are underlined in red, and with a right-click of the mouse, Firefox offers a short list of possible replacements.