Tap Tap Revenge the second-most downloaded free application of the year from their App Store, and the most downloaded free game. In April 2009, internet marketing research company comScore announced the results of a study which claimed 1 in 3 U.S. iPhone OS users had downloaded the game, and that it was the most popular application for the iPhone and iPod Touch. As part of the 2nd generation iPod touch advertising campaign, Apple featured "Tap Tap Revenge" in print and television ads with the headline "The funnest iPod ever.". The game spawned three direct sequels, "Tap Tap Revenge 2", "Tap Tap Revenge 3",
IPhone placement of the microphone and speaker on the base on the unit—the speaker is on the right. Volume controls are located on the left side of all iPhone models and as a slider in the iPod application. The 3.5mm TRRS connector for the headphones is located on the top left corner of the device for the first five generations (original through 4S), after which time it was moved to the bottom left corner. The headphone socket on the first-generation iPhone is recessed into the casing, making it incompatible with most headsets without the use of an adapter. Subsequent generations eliminated