This is a good question! I think there are a lot of factors as to how many responses a thread gets. I have a lot of friends from this forum (most of them have become friends on facebook or in person, so we communicate that way more). If anything, I tend to not respond to threads that they post, because it's something we've discussed in other venues. I do think sport people/working people/pet people all tend to "band together", but more out of common threads of conversation and common interests... and the sport people tend to meet each other in real life for trials and such.
I think when someone posts (time of day) and the wording of the subject line tend to be what determines who gets the most views/responses... as well as how "hot button" the topic is. If it's a question that's been asked a thousand times over, people usually don't respond as often. Posts that get put up during "off" times tend to not get as much traffic either... nobody's around to see them, and when people log on they tend to go right to the threads they last participated in.
Go ahead and try posting a location thread! There are a TON of users from your area here. I actually got to know most of my "friends" through off-topic chat threads.... there were people who stood out during dog discussions, but more of their personalities (and common things that make people gravitate together, like hobbies and whatnot) come out in chat threads.