Firefox 4 to be released March 22, will it beat IE9?
This isn't to say that Firefox 4 RC is bug-free, but it does mean that there are no significant issues that would warrant an RC2. The only real issue that the Mozilla Dev mailing list has been dealing with is Vietnamese localization, which looks like it will be bumped back to Firefox 4.0.1.
In other news, all eyes are now on Mozilla to see if it can match Microsoft's opening-day salvo of 2.3 million IE9 downloads. The last major release of Firefox, version 3, recorded 8 million downloads in 24 hours, a world record that might be hard to beat.
It's worth noting, too, that Firefox 3 supported Windows XP and Vista, which accounted for something like 90% of the PC market at the time. IE9's 2.3 million downloads are pretty impressive when you figure in the fact that it only supports Windows 7 and Vista -- which together only represent about 34% of the PC market. Believe it or not, Windows XP still accounts for over 55% of PCs, and given Firefox 4's support for XP, it would be shocking if it manages less than 2.3 million downloads.
As for why Microsoft dropped support for XP is another question entirely. In a few months we'll be able to see whether it made the right decision or not.