This snippet taken from The Definitive Guide to Building a Windows Server 2008 Infrastructure, a free e-book sponsored by Tricerat. Get your free copy of the entire 10-chapter bookhere.

What we haven't discussed yet with GPPs has to do with one of their greatest strengths. Unlike most of traditional Group Policy, GPPs have the unique capability in that they can be configured to be mere "suggestions" rather than enforced "policies" as we're used to seeing. Consider the situation where you want to "suggest" an initial environment variable setting for users, but allow them the ability to later change that setting if they desire. Using traditional Group Policy, this is not possible because traditional Group Policy is intended to be an enforcement mechanism. Each time the Group Policy Refresh Interval passes, the Group Policy client will change any modified settings back to their initial configuration.

The image above shows the Common tab found within all GPP settings. There look for the configuration titled Apply once and do not reapply. By checking this box, the GPP will make the configuration change, but it will not reset that change if a user later decides that they want to change their setting away from what you "suggest".

BE AWARE: The client-side code required to process GPPs is natively available within Windows Server 2008. However, Client-Side Extensions (CSEs) must be downloaded and installed to all other operating systems for them to recognize and process GPPs. You can find links for CSEs at: http://support.microsoft.com/kb/943729.

In tomorrow's conclusion, we'll talk about GPP targeting, which eases the process of applying GPPs to the correct machines...