Sean’s point is valid: unified interfaces are more scalable than typed objects. But the truth is that it is not enough. HTTP has 4 verbs: GET, PUT, DELETE, POST. MOM as 2 verbs: SEND and RECEIVE. Does it mean that integration is easy now. No! We have just move the complexity somewhere else. The patterns related to the design of integration applications are far more complex than simple state transfer.
Certainly, as there’s the issue of how one integrates that state once its received (ala topic maps, and the Semantic Web). But complexity hasn’t been moved, it’s been reduced, because a very important problem – how one gets and submits data between applications – has been solved (to be clear, I mean solved by HTTP, not by Web services 8-).