There are a lot of changes in Microsoft Office 2010 compared to Office 2007.
The ability to create document workspaces.
The ability to create shared attachments in Outlook.
The ability to invoke actions on Microsoft SharePoint Foundation by using the Document Management pane.
The functionality that enables the local copy of the document to synchronize with the server copy.
Key Management Service (KMS). KMS uses a KMS host key to activate a KMS host computer and establish a local activation service in your environment. Office 2010 connects to the local KMS host for activation.
Multiple Activation Key (MAK). With a MAK, clients activate Office 2010 online with the Microsoft hosted activation servers or by telephone
A combination of KMS and MAK.
Data Execution Prevention (DEP) support for Office applications A hardware and software technology that helps harden the attack surface by preventing the execution of viruses and worms that exploit buffer overflow vulnerabilities.
Office file validation An Office software component that helps reduce the attack surface by scanning files for file format (file fuzzing) exploits before the files are opened by an application.
Expanded file block settings A suite of Group Policy settings that helps reduce the attack surface by providing more specific control over the kinds of files an applications can access.
Office ActiveX kill bit An Office feature that administrators can use to prevent specific ActiveX controls from running within Office applications.
Protected view A sandbox environment that helps mitigate attacks by enabling users to preview untrusted or potentially harmful files in a secure viewer.
Cryptographic agility for Microsoft Excel 2010, Microsoft PowerPoint 2010, and Microsoft Word 2010.
Trusted time stamping support for digital signatures.
Domain-based password complexity checking and enforcement.
Encryption strengthening enhancements.
Improvements to the password to modify feature.
Integrity checking of encrypted files.
Two architecture-specific versions of the OCT, one for 32-bit Office 2010 and one for 64-bit Office 2010. The 64-bit version of the OCT supports 64-bit client editions of Office 2010, and provides the same user interface, capabilities, and OPA settings as the 32-bit version. The OCT files are located in the Admin folder under the x86 (32-bit) and x64 (64-bit) folders, respectively.
For information about 64-bit Office 2010, see 64-bit editions of Office 2010.
Import feature that lets administrators import 32-bit OCT customization (MSP) updates into the 64-bit version of the OCT and 64-bit MSP updates into the 32-bit version of the OCT. This allows administrators of mixed environments (32-bit and 64-bit) to do the Setup customizations one time. For more information, see Import an Office 2010 Setup customization file.
Support for adding multiple Outlook e-mail accounts.