Duplicate downloads were discounted (probably the extra 0.3m moz claimed). How many downloaded it and not installed it is the question you may wish to ask.

And, el'reg, you of all people should know the importance of setting this record.

It's nothing but a PR campaign. Everytime it is in the news, people will look and say...

"Ooo, look, 8m people use it, I might give it a go." Hello mindless sheep, I'm looking at you!