Considering data is key when deploying a successfull SOA.
Sometimes services encapsulating data tend to reinforce silos instead or reducing them.
This is a kind of paradox but this is true.
A real data strategy should be at the heart of SOA, before anything else.
As I always said, data has been the failure of most large architectures: CORBA, EJB, etc.
NB: seems to me in the .NET world, data is now considered as a first citizen.