PPT Slide
What does it mean to publish some RDF?
You could be saying: I am asserting this. Infer what you like from it.
You could be saying: I am asking about this. Can you infer it from anything?
The model theory works equally well in either case, but the proof techniques differ.
In making an assertion, anonNodes behave very much like urirefs: they both act like logical constants, and cannot be validly bound to new values at inference time.
In making a query, anonNodes are treated as genuine variables, and can be bound to new values in order to make inferences possible.