iAd allows users to stay within their app while engaging with the ad, even while watching a video, playing a game or using in-ad purchase to download an app or buy iTunes content. iAd require iOS 4, which will be a free software update via iTunes 9.2 or later for iPhone and iPod touch customers. iOS 4 will work with iPhone 3G, iPhone 3GS, iPhone 4, and second and third generation iPod touch (late 2009 models with 32GB or 64GB). Developers who join the iAd Network can easily incorporate a variety of advertising formats into their apps. Apple will sell and serve the ads, and developers will receive an industry-standard 60 percent of the iAd Network revenue, which is paid via iTunes Connect.