A topic that often comes to the forefront in this hobby is the sharing of locations. You know where your locations are, and if you post pictures of them on the Internet, many people are going to want to know where it was. It's natural. People are curious, and it's a sign that they're truly interested in the place you photographed.
There are a few very good reasons not to divulge your locations to people, particularly not in a public forum. First, the more people who know where the location is, the higher the probability that the location will get trashed. As more people know, and tell others, and more people visit, inevitably there will be an unwanted element who will vandalize the place and keep others from enjoying it as you have.
Second, if at some point someone has an objection to the tourists coming to check out this location, they're going to ask where they found out about it. Who's on the hook? You.
Third, with greater attention to a property, the higher the probability that it's going to be seen as a risk, and will be boarded up, monitored, or generally better secured, denying it to everyone.
So, the question is, do you tell them? There's no easy answer to that question, but I'll tell you my personal guidelines developed over my few years of exploring.
To begin, I think each case must be examined on its own merit. Is the requester someone you know? Is it someone who's habits and participation in the hobby are known to you? If so, perhaps you'd be willing to share. Remember that you will also one day wish to know where a location is that someone else posted.
Beyond that, think about the nature of the location. Is there anything that can be damaged by a general awareness of its existence. If we're talking about concrete ruins, for example, there's probably little concern about damage, or an owner wishing to secure it better. Is this a place that's already generally well-known, or a very simple Google search away from being known? If so, the person requesting the information might be as well off doing a little independent research of their own, but you still might be willing to share.
Think carefully about your decision. It may impact your ability, or that of others who find it on their own, to enjoy the location in the future.