If agreement votes aren't going to be used, why not do away with them altogether and just use the current system to vote based on quality only?

I like Jess's proposal because I think it has a better chance of working in practice. Most of us, I think, do want to express agreement / disagreement, and I think separating it out into a separate vote would work better with real humans' cognitive systems than relying on people following an explicit instruction to ignore one of their motivations. [Yes, I would like to see a study testing this assumption somehow, but in the meantime, that's the prediction my subjective probability is going into...]

Besides, I would find the agree/disagree info interesting. And I think it probably reduces "me too" posts. And the info presumably could be used for the "most controversial" page.

(edited: s/separate out their motivations/ignore one of their motivations/)