At some time during the middle of last week -- quite possibly, on the very day that Microsoft announced its settlement with the European Commission -- Web analytics firm StatCounter registered more Web site hits coming from Web browsers announcing themselves as Mozilla Firefox 3.5 than from either Internet Explorer 7.0 or IE8.
According to the fairest interpretation of StatCounter's data, that means Firefox 3.5-branded browsers are more actively used, on all platforms including Linux, than any single version of any other browser, including IE. As of Monday morning, FF 3.5 was responsible for 21.93% of HTTP requests tracked by StatCounter, versus 21.2% of requests from IE7, 20.33% from IE8 (buoyed recently by Windows 7's success), and 13.89% from IE6.
Calling this a "market share" assessment is a stretch, since markets are typically comprised of users, not their transactions. Arguably, Firefox users are more active on the Web, thus it may not follow that there are more Firefox 3.5 users than IE7 users, nor that there are more Firefox 3.5 installed browsers than IE7 browsers. Nonetheless, it's another significant threshold for the leading alternative browser on the Windows platform, and the leading browser for Linux.
When you combine version numbers together, Internet Explorer still comprises 55.42% of Web traffic that StatCounter tracks, versus 30.94% for Firefox 3.5 and 3.0 browsers combined. Firefox 2.0 browsers have dropped off the chart.
StatCounter's statistics are not backed up by NetApplications, however, which strangely tells an opposite story. After having jumped over the 25% last week, all collective versions of Firefox dipped back to 24.72% usage share in the NetApplications count for this week. IE6 remains the most used browser tracked by that firm, with 22.08%; IE8 has 19.34%, jumping over IE7 with 16.86%. Firefox 3.5 has just 15.16% usage by NetApplications' count. It's believed that NetApplications tracks more "corporate" users.