IMHO making an
actor the output, not a
consumer of the output, kinda makes the output an end in itself. It also negates analysis of output
requirements and identification of the development project's
stakeholders.
From the OMG UML 2.0 Spec. on
Actors:
An Actor models a type of role played by an entity that interacts with the subject (e.g., by exchanging signals and data), but which is external to the subject (i.e., in the sense that an instance of an actor is not a part of the instance of its corresponding subject). Actors may represent roles played by human users, external hardware, or other subjects. Note that an actor does not necessarily represent a specific physical entity but merely a particular facet (i.e., “role”) of some entity that is relevant to the specification of its associated use cases.
I have difficulty thinking of
output as a
role.
Output is just a highly structured message [signal], perhaps with deep content, from the system to the actor. I'm sticking with my use of the directed line from the system to the consumer as being the output, just as the information flows along the lines in an activity diagram.
However, another way to think of this is that
messages are also
objects that normally have structure. These
serialized objects move between systems and actors along the lines of which I speak.
Then, again, all of this discussion, so far, is moot if the question was asked within the context of Business Process Modeling. Those models have their own diagramming elements...