As I've written before, I find that if I post an answer that took me a few seconds to find out (by simply entering a few key words from the question into Google) I generally get loads of thanks.
However if I spend hours researching a detailed answer to a question (or even, as I have done, drive many miles to find something out) I can almost guarantee that I'll get no response at all!
It never really bothers me that much, although I have to admit that I was a bit miffed when an American ABer, whom I'd given a guided tour of Paris to, didn't respond to the Christmas card I sent him later that year!