GAT+ has now extended email auditing with two new reporting features relevant to Google Groups. You can now search for emails that contain an internal group as a sender or receiver in some position. Just check the ‘Groups’ tick box and press ‘Search Emails’.
Once the results are back, you can click on the ‘Sender/Receiver’ Table button, to see the groups listed along with the date and time the group was last used as a sender or receiver of an email. Email counts are also reported.
This is a useful feature for identifying redundant groups in terms of email.
Before you go deleting the idle groups, DO NOT forget groups are also used in Google for file sharing.