FYI - I think it's also important to realize that the # downloaded could very well be geographically centric.
Meaning - http://www.apple.com/euro/itunes/charts/apps/top10appstorefree.html
Notice a trend there. The app is # for free apps NOT in the USA.
I dunno, these sales look very inaccurate. Google Maps gets 10 million downloads in 2 days, but only shows up in the Top 10 of a few random countries. I would have at least expected it to crack the Top 10 in every country (not just Greece, Luxembourg, Switzerland, Ireland, New Zealand, and Australia). Maybe these Top lists are based on staggered weeks.