Windows Communication Foundation offers an amazing variety of extension points but due to limited documentation most developers treat it as a black box. There is some information in MSDN, but it is far from adequate. Carlos Figueira intends to change this with a series of articles on WCF Extensibility.
Carlos has already posted four chapters on behaviors and service model extensibility. After discussing each of the behavior interfaces in depth, he provides a real-world example of building your extension. The scenarios he covers so far include:
POCO Service Host: Demonstrates offering a service without the need for ServiceContract attributes.
Alternate Serializers: Replace the default DataContractSerializer with XmlSerializer or NetDataContractSerializer
Endpoint Help Page: Create a new help page when users access the service via a web browser
