We knew iPhone sideloading was inevitable in Europe long before Apple actually announced the feature. By sideloading, I don't just mean the ability of an iPhone user to download any application regardless of the source.
Yes, iPhone owners in the European Union will be able to install apps from the App Store, third-party App Marketplaces, and developer websites. But I also mean support for third-party payment systems and the ability for developers to place links in their apps to their websites...