Just over a year after the original iPhone OS's release came version 2.0, which introduced the App Store. The next year saw the debut of iPhone OS 3, which added long-awaited features like Cut, Copy and Paste and MMS support; it also introduced push notifications. The last feature was the most important of the release; it meant that all the apps you installed could finally alert you to important events (new instant messages, your turn in a game) even when they weren't running. It wasn't multitasking in any sense of the word, but knowing that your apps could alert you when you weren't using them was a significant improvement.
iOS 4 made numerous changes: The OS's name changed, multitasking arrived, and FaceTime was unveiled. Multitasking eliminated the feeling that certain iOS activities--copying text from Safari to paste into an email, for example--were too much of a chore. iOS 4 also meant folders, a unified inbox in Mail, iPod controls to the left of the multitasking bar and systemwide spellcheck. These are all features that active iOS users still use, every single day.
In some ways, iOS 4 mirrored elements of OS X's Jaguar and Panther releases. FaceTime on iOS clearly owes a debt of gratitude to iChat AV on the Mac. And Exposé--though clearly different--influences iOS 4's multitasking bar.
iOS 5, in this analogy, is Tiger. Where Tiger offered .Mac syncing, iOS 5 introduces iCloud. Tiger introduced Dashboard, for easily accessible widgets of up-to-date information; iOS 5 has Notification Center. Both OS releases add system-wide dictionary lookups.
Tiger also included VoiceOver, which the iPhone inherited with the release of the iPhone 3GS. But both the Tiger release and the iOS 5 release--at least on the iPhone 4S with Siri--introduced new, useful ways that your Apple devices could speak to you.
Here's a fun thought experiment: Name the single most important release of iOS. I bet you can't do it. Obviously the original launch was of huge significance, but then, so was the App Store release in iPhone OS 2.0, and multitasking in iOS 4, and so on.
Each release added new delights. iOS's upgrade pace is more dramatic--and more joy-inducing--than iPhone hardware upgrades. With each subsequent incarnation of iOS, you can't imagine going back to the one that preceded it; the new stuff awes you, and quickly becomes second-nature and necessary to your iOS enjoyment. An iPhone 4S user wouldn't want to give up that phone to go back to an iPhone 4, but could make it happen. Put an iOS 5 user back on iOS 4, however, and expect some tears.
So when you marvel at how far iOS has come since 2007, take a moment to appreciate not just the journey, but the fact that each step along the way has been insanely great.
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