[via BetaNews]

Two and half months after Firefox’s 1.0 launch, the Mozilla Foundation has more to celebrate than non-stop media coverage: Firefox has surpassed 20 million downloads. The milestone comes just days after new tallies of Web browser usage shows strong gains by the open source newcomer, which is slowly chipping away at Internet Explorer’s dominance.

Last November, Microsoft IE product manager Gary Schare told BetaNews, “We think that getting the first set of early adopters is a lot easier than getting the next set, and then crossing over into the mainstream is pretty difficult.” But Firefox is refusing to relent, garnering up to 270,000 downloads per day.

In the past month alone, Microsoft’s IE market share has dropped 1.5 percent, according to WebSideStory, while Firefox has picked up a full percentage point. In an interview with BetaNews, Firefox architect Blake Ross said he expects the browser’s growth “to remain vibrant as more and more people learn about Firefox and tell their friends and family members.”