Global usage share numbers released Monday by OneStat.com showed Mozilla Foundation browsers increasing to a 7.4 percent share from 2.1 percent in May. Meanwhile, Microsoft Corp.s Internet Explorer dropped 5 percentage points to 88.9 percent during the same six-month period.
OneStat.com, an Amsterdam-based Web analytics vendor, based the usage share number on a sample of 2 million visitors across Web sites in 100 countries.
The latest usage statistics follow market-share numbers from another Web analytics provider, WebSideStory Inc., that showed Internet Explorer declining about 3 percentage points since June as Mozilla gained steam.
OneStat.com specifically cited Mozillas Firefox browser as one reason for the usage shake-up. The Mozilla open-source project released Firefox 1.0 earlier this month.
Firefox held a 5.6 percent share in the latest OneStat.com data, putting it halfway toward reaching a Mozilla goal of having a 10 percent Firefox share in 2005.
"It seems that people are switching from Microsofts Internet Explorer to Mozillas new Firefox browser," OneStat.com co-founder Niels Brinkman said in a statement. "The total usage share of Microsoft declined 5 percent, and the total usage share of Mozilla increased 5 percent."
Browsers from Opera Software ASA held a 1.3 percent user share in the OneStat.com report, up from 1 percent in May. Apple Computer Inc.s Safari browser also made a slight gain, rising to 0.9 percent from 0.7 percent.
Microsoft has begun responding to Firefoxs growing popularity. It has started to tout the wide range of add-on software available for Internet Explorer that gives users new features, including ones such as the tabbed browsers that are popular in Firefox.
A Microsoft executive also has said that the Redmond, Wash., company is considering launching new features itself through the add-on architecture ahead of the next major release of Internet Explorer, which is slated to coincide with the 2006 Windows Longhorn release.
For its part, Mozilla is continuing to tout the momentum of Firefox. Over the weekend, Mozilla release manager Asa Dotzler wrote in his Weblog that Firefox 1.0 had reached 5 million downloads since its launch.
The Mountain View, Calif., group also has held a series of Firefox launch parties worldwide and is planning the publication of a New York Times ad funded through donations in the coming weeks.
Also on Monday, desktop Linux vendor Linspire Inc., of San Diego, announced a new software bundle that combines Firefox 1.0 with open-source productivity suite OpenOffice.org 1.1.3. Called OOoFf!, it is being sold in retail stores and supports the Linux, Windows and Mac OS X operating systems.