Groupon and Ebay don't violate Apple's iAP policy. Apple's iAP policy specifically prohibit purchasing content, functionality, or services in an app with a mechanism different than Apple's iAP (section 11.2 in Apple's iOS Review Guidelines).However, section 11.3 in Apple's iOS prohibit the use of iAP to purchase physical or digital goods and services used outside the app.Therefore, Groupon and Ebay follow exactly according to Apple's policy.A link to Apple's iOS Review Guidelines (Apple developer account required):https://developer.apple.com/apps...