Why wouldn't the same topics come up repeatedly? Bears are still there and the population of the internet changes daily. What is an old discussion for one is new to another. Also people move in and out of conversations as topics become relevant to them. For example while I've always respected and admired bears in general in the past I hadn't been very concerned with the notion of bear defense since there aren't many bears in MN or SD. In a week or so though I will be hiking and camping in bear country for the first time so now it's relevant to me.