What is jailbreaking? What does it do, and why was it illegal?
Jailbreaking is when you do something to your iPhone that enables it to connect to other phone carries, like T-Mobile or Sprint, something like that. It also has it's own little app store for free, exclusive apps that do certain stuff to the iPhone to enhance it or make it awesomeness.
So wait, if I had bought an iPhone I could use it on Verizon?
Yes. All you would need is a Verizon SIM Card though.