[dragonwriter]

> Up/Down voting on HN and most other sites makes me think of the Yo app, where there are simply too few choices to express what you wish to say.

If you wish to say something more than up/down votes, that's what the "reply" function is for.

[avalaunch]

No, the reply function is for when you have something meaningful to add. If all you have to say is "I agree/disagree" or "your comment was useful/not useful", the reply function is not the right function to use. But unfortunately, the up/down functionality isn't quite right either because you can't determine why the vote was cast.