Many of the features that are new to iOS4 seem to have originated from jailbroken applications and utilities. Has Apple been adopting the ideas of jailbroken developers and implementing them into firmware updates? Or, are these features that were likely to be implemented at some point anyways? It’s your call.

1. Folders
Folders, which allows you to group similar applications together, is a non-jailbroken copy-cat of Categories, which is available on Cydia for jailbroken devices.
2. Rotation Lock
Double-tap the home button and you’ll find a new Orientation Lock button. By tapping this button, your device is now locked in portrait mode. No more awkward positions when you’re lying in bed — you weren’t the only one. Nevertheless, jailbroken users have had this utility for quite some time through SBSettings/Rotation Inhibitor.
3. Home Screen Wallpapers
You’re 3 years late on this one, Apple.
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4. Battery Percentage
iOS4 allows you to see the exact percentage of battery life remaining on your device. While this is much more accurate than the battery icon next to it, it’s something jailbroken users have been able to do for years.