I'm sure this gets asked a lot, but its something I'm ignorant about. I do understand the premise of a trademark as being protection for a commercial brand from being used by a competitor and assuring consumers that a product is the real deal. The thing I want to know, is to what extent or degree a writer may use the name of a real-world business in writing. Naturally I mean in a neutral non-derogatory fashion. My story takes place in a realistic present-day setting and I would love to subtly describe it by sprinkling in things like "It's next to the empty Walmart". With these six words one immediately has an image of a specific kind of area within an older suburb or small town. Of course I've read plenty of stories where this is done, never mind things like newspaper and online reviews of restaurants and stores. But is that under some kind of fair use principal, or are the rules hard and fast and I can know I am doing things right(or wrong)?