Firefox Keeps Slicing Into Internet Explorer Market Share

According to data from San Diego, Calif.-based WebSideStory, Firefox -- the Mozilla Foundation's upstart stand-alone browser -- saw its usage share jump from 3.03 percent in early November to 4.06 by early December.

That 34 percent gain compares to the previous month's measly 13 percent increase. "Firefox's gains are accelerating," said Rand Schulman, WebSideStory's chief marketing officer, in a statement.

Schulman attributed the boost in Firefox's share -- Firefox still badly trails Microsoft's Internet Explorer, which in early December had 91.8 percent of the U.S. browser business -- to the November 9 release of the final 1.0 version.

"Firefox's stated goal of gaining 10 percent of the market over the next year no longer seems unattainable," Schulman added.

Virtually all Firefox's growth was at IE's expense, said WebSideStory's data, which noted a 1.09 percent drop in Internet Explorer's share during the same period. Since early June, WebSideStory's numbers have tracked a 3.7 percent drop in IE's domestic usage share, with a nearly-identical rise in the use of Mozilla's browsers.

Firefox 1.0, available free of charge in versions for Windows, Mac OS X, and Linux, has been downloaded more than 10 million times, a number nearly double that of just three weeks ago.

IE has been plagued by several security vulnerabilities since mid-summer, 2004, that have sent some users scrambling for an alternative. Last week, for instance, Penn State University urged its 80,000+ students and staff to dump IE and replace it with a non-Microsoft browser, such as Firefox, Mozilla, Opera, or Safari. Other monitoring firms, such as OneStat.com, have reported an even more precipitous decline in IE usage worldwide. Late last month, the Dutch-based vendor said that IE's share had dipped under 89 percent, and had fallen 5 percentage points since May.