No Fixed Address

All content out there on the web has a fixed address. But the objects that reside in the implementation of these web resources do not. At least not in a URL-sense. These are objects that live in the database, in cache, or in the web server's memory, as part of an intermediary step toward the finished product that is ultimately delivered to the client. What these objects do have that strikes a similarity with URL-thinking is a unique identifier. These identifiers tell us that this object has it's own state, unique to itself in some context. The context in which these objects are unique is usually constrained to the application. For instance, the primary key that identifies a row in a database table is a common object identifier. The context in which we're assigning identifiers to objects is growing more important, as time moves on, because there is a growing need that the applications we develop integrate seamlessly with one another.