Audience and Ong

So I’m pretty sure I’m following what Ong is saying about the audience being both a role the actual reader assumes once he commits to the book as well as a fictional reader the writer has created filling some sort of role, like, “entertainment seekers, reflective sharers of experience, inhabitants of a lost and remembered land, etc.” (p.12) So the audience is a collaborative effort between both parties, the writer creates the role and the reader assumes that role.  Just wondering if the categories from the latter “audience” are equivalent to genres?  If so, as a writer could the audience we picture just be readers of a specific genre like sci-fi or fantasy, or is the audience more specific than that?  Does Ong’s definition of audience go deeper than just readers of a genre and more so focus on the audience (role) the author has created?  Can it be both? 

I wonder because Ong also mentioned that you shouldn’t think of a specific person, like a man on a subway, or woman in a book club, so how specific can you be when deciding the audience you want to write for?  If it’s the author’s choice, why does Ong insist upon emulating previous writers constructed audiences?  Can’t we just create our own audience as writers?  I feel that normally when I write I do so in a way that I can understand, a way that if I picked up one of my random ramblings, I would get a sense of what and how I was trying to communicate.  When I look at this method now through Ong’s perspective, I feel like it’s not completely effective.  After all experiences vary vastly between individuals, everyone has their own respective beliefs, views, interests, affinities, dislikes, coping mechanisms, the list goes on and on. Just working through this question I think I have found my answer, looking to past examples of successful writers can help you identify a style or voice that resonates with you, and as a writer you can try to emulate this style (audience created by a pervious writer).  Also it is possible to employ your own original technique (create your own audience), and the specificity of the audience is up the writer as well.  I think that genres could serve as a category that could help to define an audience, in a broad sense, but that a more specific image of a type of reader is required for successful writing.