Read about it here.
An excerpt from the entry in question ....
Google's recently acquired Postini, a leading communications security and compliance company, and added policy management and message recovery to Google Apps. This allows a firm to establish rules to automatically handle messages by sender, recipient, attachments or the contents of the message.
For example, e-mail messages with specific words can be blocked from reaching external addresses and custom filtering rules can be added to complement the spam and virus protection already present. Also, a firm can search for messages across its entire domain and recover deleted e-mail on a 90-day, rolling basis.
Ed Brill (a fellow paid by IBM to puff Notes) has a blog which has an entry (comment 14) that led me to this. So many crazy people out there!