Open-source software group Mozilla.org said Friday that its Firefox Web browser has been downloaded 50 million times since its release in November. The group attributes the popularity of its browser to the evangelism of the nearly 100,000 people participating in its "Spread Firefox" campaign.

Mozilla has deemed the campaign, aimed at "wresting control from a monopoly that has let [Web technology] stagnate," a success so far, though its gains have been slowing recently.

Earlier this week, Web-analytics firm OneStat.com reported that Firefox had captured 8.69% of the global browser market share. That represents a 0.24% increase since February. In the period between November and February, Firefox usage grew at a rate of more than 1%.

A month ago, 35.9% of visitors to the Boing Boing blog were using Firefox. Today, that number stands at 38.1%. During the same period, 34.5% of the site's visitors used Internet Explorer, compared with 36% today. While individual site statistics may not be representative of trends derived from broader data sets, these numbers suggest Firefox's gains aren't all at Microsoft's expense.

Though its reputation has been somewhat diminished by the Firefox rebellion, a long period without active development, and vulnerabilities that led security organization CERT to recommend a more secure browser, Microsoft's Internet Explorer remains the most popular browser, with a global market share of 86.63%. It is worth noting, however, that Internet Explorer's presence on a given system may not reflect the user's choice since Microsoft's browser is installed by default.

The real test for Firefox will come later this year when Internet Explorer 7.0 is released.