One in every four people on the Internet are now using Mozilla's open-source Firefox browser, a Web metrics company said this week.

Firefox reached the 25% milestone on Sunday, said Vince Vizzaccaro, executive vice president of California-based Net Applications, which measures browser usage by tracking the machines that visit the 40,000 sites it monitors for clients.

"We always thought that Firefox would be in a great position to compete with Microsoft's Internet Explorer if it made 10%," Vizzaccaro said today. "Now one in four people globally are browsing the Internet with Firefox."

Mozilla passed the 10% market share mark in March 2006, said Vizzaccaro.

The move past 25% wasn't a surprise. Last month, for example, Net Applications estimated Firefox's share as slightly over 24%.

Mozilla also touted the milestone. Mitchell Baker, the former CEO of Mozilla Corp. and the current chairman of the Mozilla Foundation, mentioned the 1-in-4 figure in a post to her personal blog earlier this week when she trumpeted Firefox's fifth-year anniversary.

Full story: Computerworld