I forgot to explain why not vote on comments. Any payout that is less than 2cents doesn't get paid out (it goes back in voting pool. Your vote at the moment is what we call "dust" so less than the 2 cent payout. It is unlikely that others will upvote a comment as well so your vote on that comment is wasted "dust". But if you vote on a post, it will join others votes and the dust piles up! Hope that helps (don't answer!) ;)
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