When you send an email to multiple people, those people can see who else got that email. But if you don't want certain email addresses to be visible to others, this is how you do it in Outlook 2010 in secrecy.
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.
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.