Answer:   A list of new features of .NET Framework 4.0:
o Improved Application Compatibility and Deployment Support
o Dynamic Language Runtime
o Managed Extensibility Framework
o Parallel Programming framework
o Improved Security Model
o Networking Improvements
o Improved Core ASP.NET Services
o Improvements in WPF 4
o Improved Entity Framework (EF)
o Integration between WCF and WF

Answer:   Some of the new features in the .NET Framework Version 4.0 are as follows:

Improved Security
Parallel Computing
Visual Basic and C# languages innovations
Performance and Diagnostics
Dynamic Language Run-time
In-Process Side-by-Side Execution
Interoperability
Profiling
Garbage Collection
Exceptions Handling
Corrupted State Exceptions
Covariance and Contra-variance
Base Class Libraries
Collections and Data Structures
BigInteger
SortedSet Generic Class
Tuples
I/O
File System Enumeration Improvements
Memory-Mapped Files
Isolated Storage Improvements
Compression Improvements
Reflection
Application Domain Resource Monitoring
64-bit View and Other Registry Improvements
Threading
Unified Model for Cancellation
Thread-Safe Collection Classes
Synchronization Primitives
Networking
Web
Core Services
New Features in ASP.NET AJAX 4
Web Forms
ASP.NET MVC
Dynamic Data
Visual Studio 2010 Web Designer Improvements
Web Application Deployment with Visual Studio 2010
Windows Presentation Foundation (WPF) Improvement
Windows Communication Foundation (WCF) Improvement
Managed Extensibility Framework
ADO.NET Improvement
Expression Trees
Support for WS-Discovery
Standard Endpoints
Workflow Services
Workflow Activity Model
Richer Composite Activity Options
Expanded Built-in Activity Library
Enhanced Persistence and Unloading