After digging deeper in these top grossing apps, you can see they consist of nearly every free to play genre there is… Social games, click games, gambling games, turn based games, card games, etc but all of these have TWO things in common: They each have lots of in app purchases and they encourage the user to buy stuff (a call to action).
Trey’s article is a wonderful look at how to make money with free to play games, an examination of why some free to play models fail, and he also throws out some terrifying numbers.
That said, I expect the Angry Birds platform to fall apart out of sheer weight. Angry Birds Space is actually really good, but I can’t see the feature film(s?), animated television show, and theme park being successful over time. I expect that the brand might just collapse under it’s own weight soon, although I hope it won’t.