Firefox 4 have beaten IE9 with the number of downloads happened in first 24 hours of their launch. More than 3 million users have updated Firefox 4 from Release Candidate versions.7.1 million is not a fake count by any third party but the official 24-hour number claimed by Mozilla.
Internet Explorer 9 (IE9) which was considered to be a huge hit by Microsoft , isnt exactly the story now. IE9 was downloaded almost 1/3rd time of Mozilla Firefox in first 24 hours i.e. 2.35 million download to be precise.
Firefox 4 Download Stats now shows more than 23.5 million downloads already and still counting more.
Though this number is still less and neither a record breaker for Mozilla. Mozilla 3 was downloaded about 8 million times in the first 24 hours of its launch on June 18, 2008 which is the record for any desktop browser yet.
Another reason for MS failure here is for the reason that Microsoft have not pushed IE9 as major update to most of the countries whereas Mozilla 4.0 pop up appears as soon as you open any previous versions of Mozilla Firefox.
You may download firefox 4.0 here.