MSExchangeTeam is blogging about some of the new cool features of Exchange Server 2010, and last week the topic was the Moderation capability.
Moderation in Exchange Server 2010
In past versions of Exchange server, the best way to control mail flow to a distribution group or mailbox was delivery restrictions. Delivery restrictions allow you to reject mail from certain individuals or groups (sometimes referred to as a blacklist), allow mail only from certain individuals or groups (or a whitelist), or a combination of both.
In Exchange Server 2010, moderation enables you to control messages sent to groups and individuals based on the human element: a moderator-not who sent it.
Moderation isn't limited to groups. Like delivery restrictions, you can also moderate mail sent to individual mailboxes or mail contacts, in the same way as mail sent to distribution groups. If you wanted to moderate mail from a mailbox/contact, you would have to set up a transport rule, where moderation is available as an action. For the rest of this post, I'll be talking about moderated groups/lists.
Read more at source: http://msexchangeteam.com/archive/2009/06/10/451584.aspx