I agree and here is my solution: two axes of moderation. The big, conspicuous, open-to-everyone up and down vote arrows feed into an agree/disagree poll whose total (agree votes minus disagree votes) is displayed by the comment.
Meanwhile, the useful/useless votes are smaller or perhaps harder to access, like the current "flag" system for comments where you have to click through to the comment's own page first. Perhaps voting either agree or disagree automatically registers your vote for useful, and to vote useless you have to click through like with "flag".
Comments
I agree and here is my solution: two axes of moderation. The big, conspicuous, open-to-everyone up and down vote arrows feed into an agree/disagree poll whose total (agree votes minus disagree votes) is displayed by the comment.
Meanwhile, the useful/useless votes are smaller or perhaps harder to access, like the current "flag" system for comments where you have to click through to the comment's own page first. Perhaps voting either agree or disagree automatically registers your vote for useful, and to vote useless you have to click through like with "flag".