What purpose does it serve, really? If you want, you can keep the feature that automatically hides posts that get a certain number of downvotes, as a form of self moderation, but don't make it public, then. Downvotes only introduces negativity to the community. People get annoyed or offended when someone else disagrees with them and shows it by clicking downvote, often demanding that they write a post to motivate their downvote. Strange reaction if you ask me, but that's beside the point. On the other hand, it's clear that there are a bunch of people who completely abuse the downvote function and use it to downvote anything posted by someone they dislike, regardless of what's posted.