Flipboard has been downloaded 3.5m times

"He revealed that the app has hit 3.5 million downloads in a year and two months, and has gone from 250 million flips per month to 550 million flips per month in the four months since June. Last time we checked in the app had seen over 2.5 million downloads and with 11.4 million “Flips” per day (which can be likened to pageviews).
The 3.5 million figure is impressive considering Apple has said that it will have sold a total of 35 million iPads in 18 months."

Source:  Flipboard CEO Mike McCue, talking to TechCrunch, 12th September 2011