Well, after having been referred to this Discussion after wondering how Karma worked, I can say that I sit in the camp that says gratuitous giving is pleasurable to me, as the giver, and is hopefully received with pleasure by the anointed member.
Maybe if this Forum had a 'Like' or 'thank you' button in order to acknowledge the poster's comments then awarding Karma could be considered and delivered differently, because for me it's serving the purpose of thank you and/or like.
I appreciate that the Karma points carried by a member are merely fluff, but they are this Forum's measure of acknowledgement for the poster's contribution/information/advice etc, and can be used effectively rather than adding a post to say you agree or like the comments.
Of course, one can do both, give Karma and post their acknowledgement.