The capabilities of Exchange Server 2010 will become available in Exchange Online during 2010. This change will bring the latest server features to the cloud, and will give IT administrators greater control, improved customization, and enhanced coexistence between Exchange Online and Exchange Server.
Exchange Online subscribers will be able to enjoy these enhancements without the effort of an on-premises software upgrade. This is one of the key benefits of an online service—you can give your users access to the latest Exchange capabilities with minimal effort.