As there is currently a weird applaud/smite counter-fest going on at this moment, I would like to take the opportunity to advise you that the karma point system around here really shouldn't be taken too seriously. It's another avenue for people to express themselves around here, but don't read too much into it - as in, don't put too much stake in getting positive or negative karma. Quantitative values such as +/- will be things that you will naturally want to use as some form of comparative basis, but I would advise against that.
That being said, I do dole out karma and thus engage myself in the 'game' if you will, as a form of expressing myself and as some means of sifting through 'posts of interest' if you will.
Long'n'short - use it how you want to use it, treat it as you want to treat it, but don't let it drive your behavior. That's all.