Last Thursday RIM announced that they have shipped 700,000 PlayBooks as of August 27th. However for developers the more important question is how many of those were actually sold? Based on my calculations the answer is that they have actually sold through most of these with 504,000 PlayBooks sold as of September 16th.
This estimation is based off of the number of downloads of the free game Pixelated. While this calculation does rely on a number of assumptions, given that Pixelated has remained one of the most downloaded apps for the PlayBook, I feel that I have better numbers then most to base this estimate upon.
I have tweaked the formula used to make this estimation, to one that is more conservative then the one I have used in the past. Under the new formula the June 14th estimate would have been revised down to 255,000 tablets sold.