That seems to be their theoretical use, much like the downvote is theoretically supposed to be their inverse.
In practice though, it seems that the users of most online communities seem to treat them as an "agree or disagree" button, with dissenting opinions typically being either forced out of a thread or languishing due to the upvote-downvote tug of war generally suppressing a comment's rankings.
In practice though, it seems that the users of most online communities seem to treat them as an "agree or disagree" button, with dissenting opinions typically being either forced out of a thread or languishing due to the upvote-downvote tug of war generally suppressing a comment's rankings.