There is a lot of noise about the Service Oriented Architecture (SOA) and much less about how to coordinate those services or how to assemble them in a logical structure. A business has no gain if SOA is implemented and that those different services are not linked to each other or orchestrated.
The Service Orchestration concept is something that exists for a long time but it seems to me that it is not applied within a lot of organizations. One thing is to have a Service Oriented Architecture implemented for you business and the other is to really reuse and orchestrate automatically your business around those services.
Service orchestration is a concept mainly used in ESBs but I do not think it should only be used and implemented there. Business Process Management (BPM) is a technology that could orchestrate the services without any problems and some ESBs are using BPM to provide the service orchestration.
A service should be seen as a step in a business process and there you go, you are free to model your services as a unique business process that suites your needs. A business process mainly needs two kind of steps, which could be manual or automatic. A manual step is where an action is needed by someone from your company or a third party.
As I am working in document management for a longer period now, I am trying to explain to my clients that they could reuse their existing services in a newly created business process where document management is also completely integrated with the whole solution. Specifically, Alfresco has a BPM solution based on the jBPM implementation and thus document management is already integrated with BPM. The only thing to do is to integrate your existing service within your business process and benefit from it as an added value to your business.
This kind of integration does not need an ESB and I am not saying that this kind of solution is equivalent to a an ESB implementation. ESBs allows you to do much more than just service orchestration but this is just to explain that SOA is not really an added value to your business if you do not have a business process management around the services.