Angry Birds Expected to Make $1 million a Month On Android Just from Advertising

Source: tech.fortune.cnn.com/2010/12/03/how-angry-birds-makes-a-million-a-month/Notes:

1. On Android, Angry Birds is given away free and derives revenue from Admob.
2. Episodic content cited as a reason why people keep continuing to play (and hence generating clicks).
3. To generate that amount of ad revenue will require 500 million downloads for most developers. That seems impossibly high. Either the numbers are wrong or they're getting much higher playing time & click-through rates than the average app out there.