Good question and you also raise a point here that I notice about many of the posts.  With no moderators, it's difficult sometimes to get timely answers.  For my two cents, I'd say that if your YA is a romance then it will get more viewers in that forum, historical then put it there, etc.  But if it's just a general YA story like say a modern retelling of Our Town, then where do you put it? 

Give a holler if you find out.

John