By my rough estimates, we achieved just above 3.5 million downloads in the first week of the Firefox 1.0 release. Averaging half a million downloads a day for the first 7 days is simply amazing!
With 1.0 we had just over a million downloads on the first day. To have something to compare to, the best single day of downloads that we had with the Preview Release was around 300,000 and it took us more than three weeks to top 3.5 million downloads.
Another interesting comparison point is that while we broke a million downloads in a single day, Apple's long-awaited iTunes for Windows took more than three days to achieve its first million downloads. We're on fire!
This is so exciting! Keep spreading the word!