Who is the Target Audience?

I'm spending a lot of time blogging, engaging writing groups, and soliciting emails from adults. I'm following the tools given to me by the wisdom of those who have already jumped on the moving train. But my brain keeps asking me, 'who is your target audience?' Occasionally, a Middle Grade reader is testing the writing waters or interested in what I'm writing. However, my marketing audience has been writers over readers. Guess who is reading this blog now? You are a writer, right?

If I'm writing a Middle Grade novel with content geared in that direction, it would make since that I market to Middle Graders. But they are a harder audience to pull from. My libraries are full of kids reading and my daughters schools are full of hopeful readers. Where is the market for them? I know some of you are getting to do live readings but that is not a buyers market. Put aside the argument, "write for yourself, not for the sale...blah, blah, blah."
We are all ecstatic to discover when someone reads our work.   
Even I have said, "I just want to be considered an author." In my head the rest of the sentence goes..."so people will read my stuff."

I know there are reader avenues to take as I mentioned before. But I'm looking for traffic that gives back at a higher percentage. So is my audience you...oh great blog wanderer? Or is it the kid who will snuggle in her nook and read his newest book? That's my conundrum for the moment. I do love a challenge.