the medium is not merely communication, it is process
twitter for example is an extended work of art by a large number of people and the more that it casually represents the threads of reality, the less use it may be. To make use of it in a traditionally advertising way seems logical, but is it?
the medium is defined by the activity people engage in
this appears self evident. Between online functionality and real world needs appears and opportunity, the process of which is financial benefit. If it fails to gather enough steam to effect change in its audience, it slogs. If the audience engages with it, it thrives.