Thanks for your answers. I guess I'll proceed like this from now on: (1) if I use only a small snippet of a comment, I'll reference both the comment and the a

Thanks for your answers. I guess I'll proceed like this from now on: (1) if I use only a small snippet of a comment, I'll reference both the comment and the author (2) if I use (nearly) the entire comment, I'll try to contact the author and present him the text and how its comment is used. The only issue in this case is that critical commentary might not be accepted. One additional argument for contacting/informing the original author is that it is simply nice and encouraging to see one's contributions making waves, something that will be much harder to hear about if the comment is only linked to.