You just bought Nexus 4 and you don't know anything about Android operating system, so I will guide you through literally first steps on this great phone.
A really useful feature in case you want to receive a warning notification before you use all of the mobile data available according to your mobile provider contract. It's a great way to avoid additional charges.
iOS6 comes with a great new feature you can use to password lock an app or only a part of the app so you can hand over your iPhone to other people without worrying they will do or find something you don't want.
