[goalieca]

There's another site similar to hackernews and their downvote button requires a reason.

One of: off-topic, incorrect, me-too, troll, spam.

I bet though a lot of people would still use incorrect for disagreements.

I always thought slashdot had a great moderation system where +5 was the max a post could get and everyone only had a few votes every few weeks so you had to be careful. The upvotes also had reasons like (insightful, funny, interesting ..) so a user could sort by those.

[DrScump]

  One of: off-topic, incorrect, me-too, troll, spam

I suggested such a metric for flags to dang over a year ago, and I wouldn't assume that I was the first to do so.