Every time I spend time with an Android phone [the back button] drives me nuts. Windows Phone seems a little more predictable, but I still think iOS has this right: let each app provide its own internal navigation between screens, and let the system provide a way to switch quickly between recently used apps.
The problem with iOS's solution is that developers can't expect users to know how to go back to the previous app. As a result, iOS apps almost never send you to other apps. This has a number of negative effects.
For example, almost every single iOS app that allows you to open web links implements its own web browser, with its own user interface, and its own set of features. So when I open a link in Facebook, I can't send it to Instapaper. Safari has the necessary bookmarklet, but I'm in Facebook's own special little browser.1
This is another case where webOS2 got it right. No cross-app back button, but still a simple way of getting back to the previous app.
Previously on this site: The Back Button Dilemma.
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