I couldn't find this topic while searching, so feel free to link me to past discussions or threads if relevant.

• I'd say if there are no or very few comments under your answer, it's usually enough to upvote that comment and leave a response comment saying that you agree & it's an important contribution. If there are many comments already then one might worry that future readers will not notice that important comment; then I don't see anything wrong with copy-pasting it into your answer (formatting it as a quote and certainly giving an attribution). Sometimes people update their answers elaborating on (as opposed to copy-pasting) somebody's comment. That is also fine. – amoeba Jan 3 '17 at 17:51
• Ok, that's fair and along the lines of what I was thinking. Just wanted to confirm. – ilanman Jan 3 '17 at 18:06
• But what if the person thinks that it is so relevant and different that he decides to submit a separate question. If you include it in your answer even though you give him credit that might discourage him from submitting the answer. Rewarding his comment with a + vote does not help his reputation. – Michael Chernick Jan 4 '17 at 0:03
• @Michael Chernick I can't see a real problem. Anyone who choses to comment rather than answer won't gain in reputation; that is correct. I can't say that ever influences my contributions. The implication is that people should write some good answers somewhere if they wish to gain reputation. Anything else looks like second-guessing about what upsets or motivates people. Anyone upset by their comment being quoted but not otherwise matched by reputation gain is not going to enjoy the site for long. Reputation is only an elaborate game with some bizarre details and several positive features. – Nick Cox Jan 5 '17 at 10:47

@conjugateprior, could you help to add a reply, so that it could benefit other people. I will mark it as answer and grant bounty points. :) – Lin Ma 17 hours ago