Jailbreaking is a term used to define the hacking of an Apple device (iDevice) to overcome the restrictions imposed by Apple on an iPhone, iPad or iPod touch and gain full access of your device.
It enables users to access new or sometimes even hidden settings with unofficial apps, maximum of which come from Cydia, which is the primary repository for these unsanctioned programs.
But this did not amuse Apple very much. It even tried to declare jailbreaking as an illegal practice. Apple has at every turn tried to patch these security vulnerabilities which the hackers use to jailbreak the iDevice. But now the company seems to be changing its policy and has probably realized that the only way to stop jailbreaking is to give the users what they want so that they don’t have to hack into the iDevices.
People who are new to iOS and have not been using iOS since its first version, might not know, but features like video recording, multitasking, copy/paste, customizable notifications and some other use features were only available to people who jailbroke their devices and added these features which were earlier not sanctioned by Apple.
Then gradually Apple integrated majority of these functions into its mobile platform with each iteration of the iOS. Now as iOS 7 nears its release, Apple has done it again.
iOS 7 has multiple enhancements none of which is an ordinary feature. Some of the features are among the most popular features which could be added only after jailbreaking your iDevice.
This clearly implies that when Apple launches the new iOS, on or around the rumored date which is September 10th, there will be very few reasons left to hack into your iDevice.