This policy setting controls whether Outlook 2007 analyzes e-mail from users' Contacts when filtering junk e-mail.
If you enable this policy setting, the "Also trust E-mail from my Contacts" check box is selected in the Safe Senders tab of the Junk E-mail Options dialog and users cannot change it. E-mail addresses in users' Contacts list are treated as safe senders for purposes of filtering junk e-mail.
If you disable this policy setting, e-mail addresses in users' Contacts list are not treated as safe senders for purposes of filtering junk email, and users cannot change this configuration.
If you do not configure this policy setting the behavior is the equivalent of setting the policy to Enabled.