It is quite possible that a technology like this will play an important role with Web services as well. I say that having written many myself, and all of them follow a very simple design pattern: complex types map to objects, all objects have primary keys, and the interface provides the classic CRUD (CReate, Update, Delete) set of methods.
Which leads me to a random thought: It is quite possible that Web services could evolve to pattern themselves after EJB design patterns (something to some extent I shudder to think about)... but the idea of "Entities" and "Sessions" may have a relevance to Web services as well. You have data stores, and interfaces for storing and retrieving them, and you have services which take action on objects.