Internet Explorer 9 could see massive market share gains with auto-selected Windows Update tonight
However, starting tonight, Microsoft is planning on rapidly accelerating IE9's market share by making it available as an Important update (and, thus, selected by default) in Windows Update. Since IE9 is available for both Windows 7 and Vista, a good guess would be that users of both versions of Microsoft's operating system will start receiving IE9 through Windows Update.
The rollout will be of the staggered variety, and as such will not reach every single Windows computer at the same time. Of course, if you've somehow become anxious to try IE9 while reading this post, you can manually download it yourself right now without waiting for Windows Update to deliver it to you.
As for how the pushing of IE9 via Windows Update will alter the new browser's market standing, we'll probably know in a day or two, so stay tuned.