This is very, very good advice. My satisfaction with debates online went up quite a bit when I realized, during those awful scenes some people like to create where they insist on disagreeing with you even after you feel you’ve adequately rebutted all their dissenting points and are yet to receive adequate rebuttal yourself, that it is OK to simply state “I don’t think there’s any point to continuing this, since I surely won’t convince you — but it is enough that I’ve laid out my thoughts for others who may happen on this conversation to compare my position with yours. I think I’ll come out favorably, even if you add whatever insult to injury after this post.”