I recently worked on an issue where a client noticed four Archive mailboxes in Outlook with her name. To provide some understanding about the Exchange environment, the servers were running Exchange 2010 SP3 RU5. Also, the users have Outlook 2010 SP1. Although the mailboxes showed her name in the display, they actually belong to her delegates. This was verified by viewing the Archive mailbox folders and their content.
Microsoft introduced the Personal Archives with Exchange 2010. In earlier releases of the product, messages were archived using 3rd party utilities. In addition to eliminating the need for external archiving solutions, this new feature removed the necessity of PST files. Also, since the Exchange Archive is a mailbox, it’s capable of leveraging built-in replication and high availability features within Exchange.
With the introduction of Exchange 2007 came many new features and improvements that help to improve productivity and management: multiple server roles, a 64 bit architecture, built-in high availabilty features (LCR, CCR, SCR and SCC) and Messaging Records Management just to name a few. Another change you will notice is with Email Address Policies (EAPs) and Address Lists.