Chrome and Safari continue to gain share of worldwide usage while IE and Firefox continue to lose. Note that statistics shifted in February 2011 a little because of updated population figures changed how much some countries were weighted.

Despite arriving a week later, Firefox 4 is outpacing Internet Explorer 9 in real-world use so far, new statistics show.

Microsoft released IE9 on March 14, and Mozilla's Firefox 4 arrived on March 22--both brand-new even by the fast-moving standards of today's software market. By month's end, IE9 accounted for 1.0 percent of browsing activity worldwide, according to statistics from analytics firm Net Applications. Firefox 4, though, reached 1.7 percent, despite its later start.

Firefox 4 has a big advantage in usage statistics over IE9: Windows XP. Mozilla's browser works on the decade-old operating system, but IE9 requires Windows Vista SP2 or Windows 7. Given that Windows XP machines represent 54.4 percent of the usage on the Internet right now to Windows 7's 24.2 percent and Vista's 10.6 percent, Windows XP is a big ally even if the growth is with Windows 7.

IE9 has injected a massive dose of new competition into the browser market. Microsoft's browser supports a raft of new Web standards, led the charge for hardware acceleration, and offers much higher performance than its predecessors. But IE still isn't the browser of the technophiles, so it's reasonable to expect IE9's usage to trail that of Firefox.

Expect usage of both to increase more when people are actively encouraged to update.

"Firefox 3.x users have not yet received a major update, but will receive it soon (usually, major updates come 60-90 days after a major release). If they check for an update manually, they of course will find Firefox 4," said Mozilla spokeswoman Valerie Ponell.

As for Microsoft, "Internet Explorer 9 will not be broadly rolled out on Windows Update until the end of June," said Ryan Gavin, senior director of IE business and marketing, in a blog post.

When all versions were taken into account, IE still leads the overall market with 55.9 percent of usage in March, with Firefox in second place at 21.8 percent. Only IE, though, ceded share to the up-and-coming browsers in the market right now, Google's Chrome and Apple's Safari.

IE dropped 0.9 percentage points from February to March, while Firefox staved off the rivals with a 0.1 percentage point gain. That's not much, but it's a stronger showing than the steady losses that Firefox has experienced since reaching its high-water mark of 24.7 percent of usage in November 2009.

Chrome continued its steady rise, from 10.9 percent to 11.6 percent. Safari rose from 6.4 percent to 6.6 percent. And fifth-place Opera stayed level at 2.2 percent for both February and March.

Net Applications' statistics are based on the activity of about 160 million visitors per month to Web sites using its services. It adjusted its technique slightly for February's statistics after the U.S. government released new per-country Internet usage statistics that the company factors into its results.

For example, IE got a small boost in February because it's widely used in China, which showed higher Internet usage, while Firefox slipped a bit.

"This adjustment corrects an increasing inaccuracy over time as population shifts occur and reflects reality more closely than unadjusted numbers," Net Applications said last month.