Everywhere you let the masses upvote and/or downvote, you're going to have the hive-mind problem. We have it here, too.

I'd propose having a separate UI for users to agree/disagree, vs. for users to flag rule breaking posts, like spam, flamebait, insults and so on. The agree/disagree count would just display a vanity number, but the rule-breaking UI would actually downweight the article or comment. You could audit occasionally and remove voting privileges from people abusing the rule-breaking UI as a "Mega-disagree."