To enable end-user group management scenarios, following controls are typically expected to be in place: GRANT/REVOKE Group creation, management and removal rights to users; CONFIGURE a Group Naming Policy to ensure consistent group naming across organization; PREVENT inappropriate terms from being used as part of group names. With Exchange Server 2010 SP1, administrators can now use Exchange Control Panel (ECP) to setup above controls and hand off common group management tasks to their users! This article walk you as the administrator, through the above controls step by step. GRANT/REVOKE Group creation, management and removal rights to users: By default, end users are not allowed to create and manage their own groups. This is controlled via RBAC through Role Assignment Policies. The Default Role Assignment Policy that ships out of the box has a number of switches that control what end users can do. The one switch we are interested in is "MyDistributionGroups" as highlighted below. As mentioned, this is OFF by default, and prevents your users from creating and managing their own groups.
Full Article: Group Naming Policies in Exchange 2010 SP1 ECP