Mozilla yesterday unleashed its latest web browser, Firefox 3.5, adding new functionality, performance improvements, support for leading-edge web standards, and improved customization options. Firefox is already the number-two browser worldwide, behind Microsoft's Internet Explorer (IE), and Firefox 3.5 got off to a rapid start Tuesday, with the browser logging more than 1.1 million downloads in the first 24 hours.

"Firefox 3.5 brings together the most innovative web technologies and delivers them in the most complete and powerful modern browser," says Mozilla CEO John Lilly. "So much is happening on the web right now, it's a great time for browsers."

Mozilla had originally planned on releasing a minor update, Firefox 3.1, to its alternative browser but switched gears and released the product as Firefox 3.5, which is considered a major release. Firefox 3.5 adds a new Private Browsing Mode, similar to IE 8's InPrivate feature, and support for the next-generation HTML 5 web standard, among other features.

Mozilla claims that Firefox 3.5—thanks to its dramatically improved JavaScript performance—is "two times faster than Firefox 3.0 and ten times faster than Firefox 2.0 on complex websites." Other browser makers, such as Chrome and Apple, have been making similar performance claims recently, and each is also touting new JavaScript engines in its products. Mozilla's is called TraceMonkey.

Speaking of the competition, Apple made waves, albeit briefly, two weeks ago when it announced that its newly released Safari 4 browser had garnered 11 million downloads in its first three days of availability. But Apple didn't reveal that most of those downloads occurred because it had force-fed the update to customers through its software-updating utility. And Mozilla put that number in perspective a day later, noting that a very minor update to Firefox, version 3.0.11, had been downloaded more than 150 million times in just 24 hours. Message received: Firefox is a big-time browser. Safari is not.

How big, of course, depends on the market. In the United States, Firefox accounts for about 20 percent usage share, compared with 73 percent for IE. But in some markets, Firefox dominates. The browser has considerably higher market share in Europe and, in some countries—such as Finland, Poland, and Slovenia—Firefox actually outpaces IE and controls close to 50 percent of the market. Firefox usage share in Australia and New Zealand is over 30 percent, as well.

For more information, and the free download, please visit the Mozilla website.