Microsoft published new version of Microsoft Exchange Server it will be version 2010.
List of the new features and functionality that are included in Exchange 2010:

New Rights-Protected E-Mail Functionality with Active Directory RMS
New Transport and Routing Functionality
New Permissions Functionality
New High Availability Functionality
New Messaging Policy and Compliance Features
New Outlook Web Access Features
New Unified Messaging Features
Web Management Interface
New [...]

Today I noticed that one of storage group on my Exchange Server 2007 was dismounted.
I tried to mount database manually but It failed.
In Event Viewer I saw this error:
Event Type: Error
Event Source: MSExchange System Attendant Mailbox
Event Category: General
Event ID: 4001
Date: 2008-09-05
Time: 12:33:22
User: N/A
Computer: …
Description:
A transient failure has occurred. The problem may resolve itself in a while. The service will retry in 56 seconds. [...]

How to create Message Classifications In Office Outlook 2007 ?
1. Creating New Message Classifications
New-MessageClassification -Name -DisplayName -SenderDescription [-ClassificationID ] [-Confirm []] [-DomainController ] [-RecipientDescription ] [-TemplateInstance ] [-UserDisplayEnabled ] [-WhatIf []]
e.g. New-MessageClassification -Name ??oProject X??? -DisplayName “New Project X” -SenderDescription “This is the message to Project X”
2. Providing Read Access to [...]

Differences Between Microsoft Exchange Server 2003 Standard Edition and Microsoft Exchange Server 2003 Enterprise Edition.
Exchange 2003 Enterprise Edition supports up to four storage groups, with each storage group having up to five databases. Exchange 2003 Standard Edition supports only one storage group and that storage group can only contain two databases.
Exchange 2003 Enterprise [...]

Exchange 2007 is the move from a 32-bit platform (Exchange 2003) to a 64-bit platform (Exchange 2007). Exchange 2007 will only be supported in production environments when it is running on an x64 edition of Windows Server 2003. The Exchange 2007 Admin only installation is supported for production when using both the x64 and x86 [...]

Do More with Microsoft Office Outlook 2007 and Microsoft Exchange Server 2007. They improve the way you share information and connect with others while increasing message security and compliance. The combination of Office Outlook 2007 and Exchange Server 2007 gives you a comprehensive time and information management solution to better collaborate with fellow workers, customers, [...]