Ehh I guess each person has his own opinion. I personally don't do it unless I have something really good to say that I feel like will help, or it's a meme I want everyone to see. I seen Jerry banfield do it in one of his videos. You can in your own posts control what comments are where by the power you use to upvote all the comments. Comment the best comments 100 and others less if that makes sense.. but someone can come and upvote above your ability to control where it goes. But if that happens, the post probably deserves it!