Microsoft Internet Explorer ended 2004 with 90.31% browser usage market share, and steadily lost ground, ending 2005 with 85.05% market share. While any company would typically be thrilled with 85% of a market segment, let's not forget that Netscape once owned a huge percentage of this same segment before IE showed up. The lesson Microsoft taught Netscape was that you can't sit on top of a strategic hill, and hope that your competition finds it too steep to climb without a strong defense. The lesson was taught, and then apparently forgotten by the teacher. Microsoft promises IE's first major upgrade in years in 2006, but has also announced that it is abandoning the Mac version of IE.

Mozilla Firefox championed the open source browser concept, breathing life back into the browser battles, and is the primary challenger to IE's dominance. Firefox ended 2004 with 4.64% of browser usage market share, started 2005 on fire, cooled off for the summer months, and ended the year surging toward a 10% critical mass after releasing Firefox 1.5. December 2005 browser usage numbers have Firefox soaring to 9.57%. In Firefox's attempt to climb the hill IE is holding, they've taken a 3 pronged approach to the attack - A strong feature set with easier usability, better security with fewer breaches, and a commitment to open source and continual improvement.

Apple's Safari browser enjoyed a highly successful 2005 as the only browser to gain market share each and every month of the year. Safari ended 2004 with 1.56% of browser usage market share and in fourth place. But, not only did Safari gain steadily to end 2005 at 3.07% market share, it also leaped past Netscape to grab the third leading browser spot. Net Applications' HitsLink also tracks operating system usage market share, and shows that Mac OS currently has 4.35% market share. With Microsoft Internet Explorer abandoning the Mac and Apple's continuing market share gains, it appears that Safari has even more growth ahead in 2006.

Netscape browser joined IE as the only market share losers of 2005. Netscape ended 2004 with 2.07% of browser usage market share, and was the third leading browser at the time. But, after an admitted error in reporting itself as either Firefox or IE to HitsLink and other browser tracking software was discovered and fixed, and an announced deal with HP to include Netscape browsers with new computers, a brief September 2005 surge to 2.16% market share was quickly halted in October. Netscape ended 2005 in 4th place with 1.24% browser usage market share, and seems to have been hit hard by Firefox's success.

Opera browser from Opera Software ended 2005 with 0.55% browser usage market share, which as exactly where it was at the end of 2004. Remarkably, Opera held steady while it completely changed it's business model during 2005, going from a choice of a free browser with banner ads or a paid browser without the banners to a free with no ads model. It appeared that the change was too late to make a dent in browser choice on the desktop and laptop. But Opera browser has a strong presence on the handheld, and as those devices start to become more prominent, Opera is in a solid niche leadership role to take advantage of it.