How does your hacker friend get that cool custom look on his iPhone?
To access the root of the iOS operating system in order to make customizations to a device. (It sounds a lot scarier than it really is.) Remember when we told you about Android Launchers? Those apps help Android users easily give their phone it’s own custom look on top of the system the phone is running. But people running iOS don’t have these apps and options. Because iOS is a universal Apple operating system that isn’t open to public contributions, launchers and customizations are much harder to make.
That’s where jailbreaking comes in. When you access the iOS operating system acting as an administrator, you can download extensions, themes and other apps to add special features like shortcuts or design tweaks to your phone. Jailbroken phones can still use iTunes, the app store, and function generally the same. Aside from customizations, jailbreaking also allows access to apps that weren’t approved for the iTunes the app store. Many of these are extensions like Android Launchers, allowing you to apply custom pieces on top of your existing OS. The Cydia app store hosts these apps and others that didn’t make it into the iTunes store.
(P.S.; Jailbreaking is different from unlocking, which frees your phone to work on any carrier — like Verizon, AT&T, T-Mobile — rather than just the one it was purchased from and is illegal if it isn’t done by the carrier.)