Less than three months after its official release, Microsoft's Internet Explorer (IE) 7 browser has crossed the 100 million installation threshold. Tony Chor, group program manager at Microsoft, said the milestone was officially reached on January 8. While the industry likes to position Mozilla's Firefox browsers as IE 7's top competition, it is technically IE 6. According to WebSideStory stats cited by Chor in a blog post, over 26 percent of visitors to U.S. websites are now using IE 7, second only to IE 6. Just a week after IE 7 was released, WebSideStory issued a press release which forecast that IE 7 was not likely to have rapid adoption based on the historical trends of IE 6's adoption rates. One of the big differences between the release of IE 7 and IE 6 is the increased competition in the browser space, thanks to Mozilla's Firefox 2.0, which was released a week after IE 7. Mozilla has not yet provided stats on how many Firefox 2.0 installations it has recorded. Initial stats cited by both Microsoft and Mozilla bloggers indicated that in the first 24 hours of launch Firefox 2.0 recorded more downloads than IE 7. Mozilla's Asa Dotzler noted on his blog that within 24 hours of launch Mozilla had recorded over 2 million downloads. Microsoft's Chor wrote on his blog that IE 7 had hit over 3 million downloads in the first four days of its release. However, IE 7 was not made available as a critical update via Microsoft's Windows Update services until several weeks after the initial release. The numbers of IE 7 users will likely also rise once the consumer versions of Windows Vista hit the shelves on January 30; IE 7 is included as part of Vista. It took Mozilla's Firefox browser nearly a year after release to hit the 100 million milestone. Neither Microsoft nor Mozilla is resting on its laurels; both have active efforts to finish new browsers soon. Firefox is expected this year while IE 8 and 9 are in planning. No responsibility can be taken for the content of external Internet sites.