I'm starting this by saying I hate that title. I hate it as a post header and I hate it as a category descriptor. (Transitional or some such would be a lot less insulting to those in that age group. If they've already been "young" adults, then how are they suddenly "new" adults?)
I've read and commented on a couple of blog posts about this subject recently, so rather than continuing to repeat myself, I'm going to do my own post.
It's no secret that NA's a tough sell - just like it's no secret that those who write college age protags are stuck in a sort of limbo where they feel they have to either age their characters up or down to fit the market. However, there are some stories that ONLY fit a young person who is tasting the first freedom (and fear) that comes with college-life, or the disappointment that comes with missing out on it.
The main problem, from a marketing standpoint, seems to be that post-high school life is so diverse that there's no real common ground that stretches across all of it. (FYI, life is always diverse. If you think going to HS in Texas is like going to a school in NYC, maybe I should explain that there's a greater difference between states than simple geography. Never mind the changes that come when you leave the country and get into 6th form schools and the like.)
So for those of you who write in this age group (I've done it myself.) let me offer what I think is a bit of logical hope: Think digital.
This goes for publishers, too.
Your core audience for "new adult" are those in college. This year's incoming freshman mark the first generation of kids born completely after the rise of the Internet; they've never lived without it. They're more comfortable with the technology required for reading e-books than any others before them. Between smart phones and e-readers (and Kindle apps for their laptops) e-books provide them the kind of convenience and portability that's necessary for college life.
Many universities are already going to e-books for their courses, so downloading a few extra titles of interest isn't a stretch.
I truly believe that, while it's an age group and not a genre, "new adult" will be the first group of books where the successes are solidly e-book (commercially published or otherwise). Sure, there will be some print ones, but given the core audience and the hectic pace of life in university, it's more likely that they'll latch onto something meant to compliment what they're already carrying and not add another ounce to their bags. (iPhone for the win - a library in your back pocket!)
College kids talk. They share. They're web-savvy and they pass on the things they like. If what they like is a well written series that stars someone they could either know, or be, then so be it. I know I'd love to have them talking up something I wrote, paper or not. I'd sure love to have them Tweeting links to an Amazon purchase page with my name on it.