That is an impressive number for a game that was "inspired" by a pipe level from Super Mario Bros, with the physics of a Mario Bros water level, and a character based on the Cheep Cheep (a flying fish, not a bird) from the same game. Add in that it is an insta-kill any time you touch anything, and you have the recipe for a hit. Of course, being at the top of the iTunes and Google Play charts for about a month will definitely help with reaching that level of revenue. The app has been downloaded about 50 million times and has garnered very high reviews in both app stores.
Maybe the most impressive of all is that the game was created by Vietnamese developer Dong Nguyen, who made the game as a part time project after school. In all, the game took him about three days to create, and now it is generating an average of $50,000 in ad revenue every day. Of course, Nguyen does openly admit that he got lucky with this game. Statistics have shown that with the glut of games and apps these days, the chances of hitting it big are incredibly low, but Nguyen has managed it.
Nguyen even said in an interview with The Verge that he feels like "Flappy Bird has reached a state where anything added to the game will ruin it somehow". He has considered adding an in-app payment to remove the ads, but might not bother. Given that quote, we probably can't expect volume controls either. Nguyen feels like he got lucky finding the right balance of difficulty and fun with this game, so he has already started thinking about his next game.
source: The Verge