I tend to do all my reading via ordering books on amazon or going to the library and neither of those has an urban fiction section. I do like to read books with protagonists from a variety of different backgrounds, so while I'm not specifically looking for the books marketed that way, I imagine I might have read some. Come to think of it, there was a series of books I read a few years back that centered around a group of black/AA friends which might have been placed in the urban fiction setting were I looking for it in a bookstore.
As for 50 Shades, haven't read it, probably won't. Not because I'm opposed to smut, more that I'm opposed to sub-par and terribly written smut.