At 500 you get the downvote. Your karma impacts how your comment is ranked on the page IIRC. Besides that it's a vanity metric. I'd actually prefer to know ho

At 500 you get the downvote. Your karma impacts how your comment is ranked on the page IIRC. Besides that it's a vanity metric. I'd actually prefer to know how many people read my comment more than I would how many people felt like giving me imaginary points over it.