The device was launched on September 5, 2007, at an event called The Beat Goes On and it is the first to add the iPhone Touch screen graphical interface experience to the iPod line. It is also the first iPod which can connect to iTunes without USB cables, as it is capable of Wi-Fi Internet. It can also wireless connect to the AppStore and purchase and download software content directly to the device, no additional transfer from the PC being required. Since its release, Apple sold over 32 million copies of the iPod Touch as of the end of 2009.
The second model of the iPod Touch was introduced at the "Let's Rock" keynote presentation on September 9, 2008. It presented several improvements from the original iPod Touch, such as a built-in speaker, external volume keys, built-in Nike+, and Bluetooth support. These are a few of the upgrades and changes the iPod Touch suffered. Another important feature of the second generation iPod is able to connect a microphone.
The third generation iPod Touch is running by default Apple's iOS 3.1 and presents further improvements to the Touch line, like voice control, light sensor, bundled earphones with remote and microphone. Although having a slightly lower battery life than the previous installment, the third generation iPod Touch comes with faster hardware (the microprocessors, graphics unit and RAM are the same as the ones found in the iPhone 3GS). The third generation comes in two models: 32 GB and 64 GB. The 8 GB second generation model was also kept. The second and third generation iPod Touches can be updated to iOS 4.x, but, however, are not able to see features that include using the camera or GPS.
The fourth generation iPod Touch comes with iOS 4.1 which adds Game Center to the Home screen. This model of the device has two cameras: one for FaceTime and one for HD photos and video recording. It also includes Apple's A4 for faster processing and a 3-axis gyroscopic sensor which helps the iPhone determine how far, how fast and in what direction it was moved in. Unlike the iPad, which supports 4 orientations, the iPod can only support 3 (portrait, landscape-right and landscape-left). The fourth generation Pod Touch also adds the ability of using the FaceTime function through Wi-Fi.