> If however there is a common data service which masters customer and > can return all 500 customer fields (or via an XSLT/XPath or other > simple mechanism) any appropriate subset then passing the id from A to > B means that there is no data schema based coupling of the services.
My worry with that is the Customer becomes almost meaningless because the data/behavior/terminology for a Customer is so different when you compare CRM to Finance. In DDD terms I'd say a single definition of Customer makes sense in a particular Bounded Context, I'm not sure if the same holds true in SOA but I think this sort of thinking is key to what Udi describes here: http://msdn.microsoft.com/en- us/architecture/bb245672.aspx#jour8autonomous03 - Colin Jack
