For example, an Iowa district court in November 2006 halted all sales of See Clearly Method kits that had been marketed for several years by a company called Vision Improvement Technologies as a way to improve vision through eye exercises.
Jailbreaking is a hack that allows developers to access the file system of your iPhone, iPad, iPod Touch, meaning the root directory. In simpler terms it means that developers can now have access to all the files on your iPhone, iPod Touch, iPad meaning they can create apps that are possible of doing pretty much anything.
Jailbreak is a process of modifying iOS to change its behavior and apple's restrictions. For ex: Apple allow to run only digitally signed apps that come from AppStore or verified sources (like enterprise apps). Jailbreak allows to run apps from 3d party App Store like Cydia - or even from any source.