I've been told off recently for not doing this, and I know what you mean. I've started reading more from people who comment because of this expectation - among some people, not all of them. It's not been bad, but it is exhausting. And the bloke who complained, Oh, honestly. It transpired that he'd only been here for three weeks, so I can't have been that bad at not engaging. It usually takes me longer than that to notice someone. His stuff was OK. That is all. OK doesn't make me want to go back and read everything he writes. It shouldn't be a burden.