Flappy Bird was one of those gaming apps that went viral. very, very quickly. Many are speculating exactly how. Although few are saying it was the reviews that...View More were solely responsible, Flappy Bird was said to have generated about 700,000 reviews in a single month for their app http://zachwill.com/flappy-bird/. An insane number for a mobile app. Part of the discussion around the high review numbers was that the app had what they call a dark pattern, which as VentureBeat put it, is when a user interface is designed to get users to do something that they would not otherwise intentionally do. http://venturebeat.com/2014/02/11/how-in-app-review-mechanics-pushed-flappy-bird-to-the-top-of-the-charts/ In Flappy Bird's case, the dark pattern was that the rating button at the end of each level was in the same position as the button you usually press to start playing. If you are an avid gamer, you know that when you want to play again, you're moving quickly. Most people will click in that same spot out of habit & in this case, they'd be directed to review the app. This could've been especially effective since it is shown after the user won a level & are in a satisfied state.