A. Group Policy preferences were introduced in Windows Server 2008 and enhance what you can do as an administrator using Group Policy. The preferences feature removes many of the actions you currently use scripts for. Whereas normal Group Policy Settings (which have been around since Windows 2000) enforce their settings and disable the ability for users to change the configuration, Group Policy preferences aren't enforced and don't disable elements of the user interface from user configuration. The Group Policy preferences feature allows you to set an initial state for a configuration but allow the users to change it.
With normal Group Policy settings, you can set some basic ACLs on the Group Policy Object to control who will apply the GPO, but this is at the GPO level and not particular settings within the GPO, and you don't have a lot of flexibility.
Item-level targeting in Group Policy preferences allows you to set sophisticated targeting for each individual preference you configure within a GPO using criteria such as IP range, if a battery is present, an LDAP query, security group membership, time, and OS. In the picture below, you can see all the items available as part of item-level targeting. You can string multiple conditions together using and/or logic.