We noted Firefox 3's spectacular eight million downloads in a day when discussing the recent launch of IE9, and that mark shall live on as a record for another day. Firefox 4 looks to have a had a thoroughly successful debut, going past the five million milestone within the first 24 hours of its release, but it hasn't quite been able to overshadow its predecessor. And before you go comparing its numbers to the latest Internet Explorer, do be cognizant that FF4 released on a