If you can know how to get a quality post and identify one if you see it, then you're up to the senior rank upwards, then you can give a karma, but we should not be biased or selfish about it, we have to give it as the same way we may want others to give on us, don't give a wrong karma on someones else post because of your personal dispute with such user, it is not good because that same law of karma may hunt you back later.