I interact with anything worth interacting with. (And honestly, then some. I put in a lot of superfluous interactions which strictly speaking aren't necessary but which I do because I feel like it. This post among them.)
But shockingly, there's actually a lot fewer of those in a game than you would expect! I'd say that at absolute most, one out of every ten posts contain something which could even marginally be considered worth responding do. And that's a generous figure. A
really
generous figure.
I'm not going to spend time highlighting things that I think are worthless. I'm only going to bother with things I see as actually meaningful.
It's a "don't interfere unless this is something which desperately needs interfering with" approach.
I won't interfere in a fight, because I want to probe both sides of the debate: all the players in it, and on what the debate is about (usually other players not currently in the debate). The result of this is that I mine info without putting much bias into it. I was distanced from the discussion, so while I may hold an opinion, I didn't influence it so my perspective when I DO give it will be both fresh and relevant.
It's a pretty efficient approach for a large theme.