I do them separately, because I think it reveals more than grouping them into fewer categories. (alephblog.com)
Physical bookstores have relatively few categories of fiction and getting misplaced in the mysteries aisle when your book is an action - filled thriller isn't the end of the world. (killernashville.com)
I find it a weak interface for browsing, with too few categories for separating apps. (bgr.com)