Firefox Market Share Increases 34%

According to a study by Web analytics firm WebSideStory, Firefox's share of the browser market grew 34% in just one month, from 3.03% on November 5 to 4.06% on December 3. Microsoft Internet Explorer lost 1.09% of its users, dropping to 91.80% over the same period. As this table shows, IE's losses have been trending and accelerating:

U.S. Browser Usage Share

Browser	12/3/2004	11/5/2004	10/8/2004	6/4/2004
IE	91.80%	92.89	93.21	95.48
Firefox	4.06	3.03	2.66	*3.53
Non-Firefox Netscape and Mozilla browsers	2.83	2.95	3.05
Other	1.25	1.07	1.03	.95

* WebSideStory did not track the Firefox browser separately until Oct. 2004. The June 4, 2004, figure includes all Netscape and Mozilla-based browsers, including Firefox.

The study encompassed 30 million daily visitors to 20,000 websites in 200 countries.
(via Alex Barnett's MSDN blog)