Jailbreaking is the process of removing hardware restrictions on iOS, Apple's operating system, on devices running it through the use of software and hardware exploits; such devices include the iPhone, iPod touch,iPad, and second-generation Apple TV. Jailbreaking permits root access to the iOS file system and manager, allowing the download of additional applications, extensions, and themes that are unavailable through the official Apple App Store.
Jailbreaking is a form of privilege escalation, and the term has been used to describe privilege escalation on devices by other manufacturers as well. The name refers to breaking the device out of its "jail", which is a technical term used in Unix-style systems, for example in the term "FreeBSD jail". A jailbroken iPhone, iPod touch, or iPad running iOS can still use the App Store, iTunes, and other normal functions, such as making telephone calls.
Restoring a device with iTunes removes the jailbreak.
"Should I jailbreak?" Jailbreaking is a very bad idea, and this article will explain what jailbreaking is and why it should not be done.
The Technical reason not to
Apple designs both the hardware and software for iPhone, iPad and iPod touch. The hardware is designed to work with iOS. When you install such unauthorized modifications, the hardware doesn't know how to handle the new software entirely, giving you unexpected results. Best case scenario, it lags. Worst case scenario, it becomes an expensive paperweight.
Other Reasons Not to
We strongly suggest not hacking/jailbreaking your device. Apple does not support it, so when you experience issues after jailbreaking, you are on your own. Your warranty with Apple is voided, so they won't repair or replace it.
Jailbreaking is removing Apple's restrictions on iOS devices (iPod touch, iPhone, iPad), or otherwise making modifications to the operating system that are not authorized by Apple.
Jailbreaking is a violation of the Terms and Conditions you agreed to in order to use your iOS device.