I tend to upvote a post when it Links an interesting article or provokes an interesting conversation, and only downvote them when they voice an convectively bad opinion (like, bigotry or other unjustified vitriol).
I tend to upvote comments when they make a good point or at least try to support their argument, and only downvote them for the same reason as posts: when they are trolling, being unnecessarily aggressive, or trying to justify bigotry with fallacious reasoning or something
What about you?
Somebody replies to a thread I made? - up vote.
Somebody replies to a comment I made? - up vote.
Somebody makes a post interesting enough for me to comment? Up vote + all other comments upvoted.
Ignorance or bad info? Downvote.
Ignorance should be corrected with information, not punished and ignored. Of course intentional ignorance should be treated differently.
I don’t see it as being mutually exclusive. :)