Since the earliest days of computing, basic system files have typically loaded to the specific addresses in memory, which makes it easier for attackers to directly change the data or code stored there. Randomizing the locations where that code resides adds an extra layer of security. That's why Microsoft has incorporated ASLR into its operating systems since Windows Vista debuted -- even Windows Phone 7 has this feature. Apple, on the other hand, has only done a limited ASLR implementation in OS X and none at all in iOS.
The debut of antid0te comes on the heels of the news that Apple has removed a jailbreak detection API from iOS 4.2. This function was used by some corporate IT departments to ensure that company issued iOS devices were not jailbroken. Apple has not said why the API was removed, but at least IT departments can breathe a bit easier as long as employees stick to antid0te for their jailbreaking needs.