While Mozilla Firefox has slowed its growth pace, the open-source browser still is making enough inroads to knock Microsofts Internet Explorer below 90 percent user share for the first time in three years.
Web browser user-share data released Monday show that Firefoxs rate of growth has dropped slightly since its Version 1.0 release. The browser had been increasing about one percentage point a month since November, but the pace has fallen this month, reports Web analytics provider WebSideStory Inc.
For the five weeks that ended Feb. 18, Firefox usage had jumped 0.74 percentage points to 5.7 percent.
That growth was enough to hurt Microsoft Corp.s IE, which dropped 0.43 percentage points to 89.9 percent, WebSideStory reported. The last time IE dropped below 90 percent in WebSideStorys surveys was in early 2002.
"Maybe the biggest story of it all is that Firefox isnt going away," said Geoff Johnston, a WebSideStory analyst.
Since WebSideStory began tracking Firefox usage separately in November, the browser has risen 2.7 percentage points while IE has fallen 3 percentage points. IE had commanded a 95.5 percent share in June before it began to drop.
WebSideStory, of San Diego, Calif., tracks U.S. browser usage based on the percentage of unique browsers hitting its network of sites. The network consists of between 20 million to 30 million Internet users each day.
Johnston attributed Firefoxs tempered growth to the typical slowdown in interest in a new software release as time passes.
Firefox also has battled recent security issues, including an Internationalized Domain Name spoofing flaw affecting non-IE browsers.
Mozilla last week issued a Firefox update to fix the problem.
Meanwhile, Microsoft appears to be getting ready to more directly battle Firefox. The company shifted it strategy this month by announcing plans to release IE 7.0, an update focused on security and to be launched outside of a general Windows release.
"There are a lot of ifs with Microsofts new browser, and it may affect Firefox," Johnston said. "But I would not at all be surprised if we see sometime in the fall that 10 percent of all browsers in the U.S. are using Firefox rather than IE."
Mozilla Foundation leaders have set a goal of reaching a 10 percent share in 2005.
At its earlier pace of growth, Firefox appeared on track to reach that milestone by midyear.
If it continues to grow between a half and three-quarters of a percentage point every month, it would reach 10 percent usage by late fall, Johnston said.
The use of other Web browsers has dropped slightly. When taken together, Mozillas non-Firefox browsers and America Online Inc.s Netscape browser recorded a 2.5 percent user share, while all other browsers such as Apple Computer Inc.s Safari and Opera Software ASAs browser posted a 1.9 percent share.