You are correct, there were multiple Firefox updates this week, and we're sorry. The first update was to fix some security holes and crashes in the previous version of Firefox. The second was to fix a problem with some websites that was caused by the first update. We're very sorry that we failed to catch this problem before releasing the first update, since we know it's a hassle to have to upgrade again so soon. Firefox 3.6 is updated whenever we find important security bugs. This has happened four times in 2010 (once in March, once in April, and twice in June): http://en.wikipedia.org/wiki/Mozilla_Firefox_3.6 All browsers are updated to fix bugs - for example, Internet Explorer updates arrive through Microsoft's Windows Update program. We are working on ways to update Firefox without interrupting your regular browsing. For more information, see: https://bugzilla.mozilla.org/show_bug.cgi?id=489138