Question: Which Platforms are supported for the IBM Social Business Toolkit SDK? Can I run the SDK on an IBM Domino/XWork server?

Answer: 
The following platforms are supported:

* WebSphere Application Server 7
* WebSphere Portal 8
* Domino Server 8.5
* Tomcat 7

So yes, you can use the SDK on an IBM Domino/XWork Server.
The SDK should work with minimal amount of work on any J2EE server. 

The WebSphere Application Server, Portal 8, Domino 8.5, Tomcat 7 are the tested versions.