What is the purpose of the WCF Activation feature?
I create a WCF service in Visual Studio 2013 and publish it to IIS. I can the add a service reference in another project and consume methods on the service. When I go to the IIS Server Manager I see WCF Activation and its two sub-items (HTTP Activation and Non-HTTP Activation) unchecked.
What are these features and how does my WCF site work without them enabled? I've looked around the web quite a bit and haven't found any definitive answers. Thanks.
Before IIS 7.0 you could only host HTTP services on IIS. If you wanted to use non-HTTP protocols (e.g. net.tcp) you had to self-host. Microsoft introduced the Windows Process Activation Service (WAS) to allow common hosting within IIS regardless of the communications protocol being used.
In practical terms, one of the neat features of this is that you can host your net.tcp WCF services on IIS and they will be dynamically activated once traffic starts arriving. Previously you had to have your service running (console app, Windows Service or whatever) before messages began arriving.
Further details can be found in this MSDN article.
If you are just running WCF services using the HTTP protocol and have those services hosted in a IIS web site, the default configuration will just work.