When I post a comment, I tend to put a lot of thought into it. Does it agree with the person? If I am disagreeing with the person, can I convince them where they are wrong in a polite way, or do I just not comment at all? Do I put a smile on their face, or make them laugh? If yes, then I most definitely will comment.
I am very wary of various projects here, but mostly I just do my own thing.