Google now is sort of an intelligent personal assistant that depending on the data that Google gathers knows you pretty well. One of the coolest functions of Google now is the voice recognition functionality.
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.
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.