Simple Introduction to Extensible Applications with the Managed Extensions Framework

Here is a excellent post from Brad Abrams explaining the Managed Extensions Framework (MEF)

“The Managed Extensibility Framework (MEF) is a new library in .NET that enables greater reuse of applications and components. Using MEF, .NET applications can make the shift from being statically compiled to dynamically composed.”
Simple Introduction to Extensible Applications with the Managed Extensions Framework