(Mom, if you are reading this, stop now, please)
Adult gaming is something I don't know a lot about, but from what I've saw, there are mostly board games, interactive animations, or visual novels, sometimes featuring non-human characters like ponies in extreme cases (How I know that? Mom, I said stop reading ;_;).
The point is that there are a lot of categories possible for those kind of games, but I think people search these games essentially to find:
-potential good gameplay
-good story and characters
-Graphic style that make you think "I can do everything you want *p*"
-naughty things (can vary, better if they can choose)
-an ending that satisfy them, by satisfy I mean them feeling it was good to be there playing that
yes, That is what I can think of, otherwise, they wouldn't search for interactive contents
(this list don't apply easily for board games, of course)