SOAP 1.2 defines how new features should be introduced into SOAP. This part of the specification targets the authors of additional specifications. Unless you’re an active participant in the W3C Web service activity, you don’t need to read this section of the spec. An extensible standard calls for an extensible implementation. Therefore, the .NET Framework SOAP implementation can also be extended. You can create custom extensions by deriving them from a SOAP extension class; you can then use your extensions for logging, encryption and decryption of Web service calls, or compression or decompression of SOAP messages before they’re processed. However, custom extensions are a separate subject, which we’ll cover in Chapter 10.