When you first turned on your Mac, or installed the OS X software, an administrator account was automatically created. If you're the only one who uses your Mac, then you may not need any of the other user account types. But if you share your Mac with family or friends, you should know how to create additional user accounts, as well as which types of accounts to create.
An administrator account has elevated account privileges, which allow the administrator to make changes to how the Mac system operates.
You only need a single administrator account to work effectively with your Mac, but if you share your Mac with others, a second administrator account can be helpful, especially if you don’t want to be your family's 24/7 IT support staff.
Creating a standard user account for each family member is a great way to share your Mac with the rest of your family. Each user account gets its own home folder for storing documents, its own set of user preferences, and its own iTunes library, Safari bookmarks, iChat account, Address Book, and iPhoto library.
Managed user accounts are similar to standard user accounts. Like a standard user account, a managed user account has its own home folder, iTunes library, Safari bookmarks, iChat account, Address Book, and iPhoto library.
Unlike standard user accounts, managed user accounts have Parental Controls, which can determine which applications may be used, which web sites may be visited, who the user may exchange email or iChat messages with, and during which hours of which days the computer may be used.
Parental Controls allow you to control the applications and web sites a user can use or access. You can also create a list of approved individuals who are allowed to email or chat with the managed user.
Additionally, you can control when and for how long a managed user can use the Mac.
Parental Controls are easy to set up and versatile enough to allow your children to have fun on the Mac without getting into trouble.