I see karma on posts fluctuating (in particular going down) more than I would expect coming from other vote-based websites. Is downvoting really used here for posts that are not spam or trolling? Or do people just change their minds a lot?
The FAQ has: We encourage people to vote such that upvote means “I want to see more of this” and downvote means “I want to see less of this.” But I guess I’m surprised if people actually behave that way? And that some posts are controversial enough to receive active downvotes vs passive ignoring.
I understand this position and it's totally relevant to the question of when to downvote. However, I don't think it has much relevance to the question of when a user should upvote. If a person isn't interested in certain genres of topics, downvoting every post on one of those topics wouldn't improve discourse; it would lead to uniformity of topics. Only the few topics for which more people (accounting for karma weights) are interested in than uninterested in would remain more upvoted than downvoted. However, with the current system most people understand that this situation is exactly what the novote is for. If one doesn't have any interest in AI research then one should filter those posts where they can and disregard them where they can't.
I like the idea of automatically figuring out what topic a post is based on the upvote, novote, and downvote patterns of different users. Maybe some combination with that and the topic tags on posts could lead to a different, individualized karma system. Votes from users with similar interest in topics would have more weight for each other than they do for users with disparate interest in topics. Seems a little echo-chambery, but I see value in the idea.
I do see a bit of a incongruity between what you're describing and the the comment you linked to which I can't square. In actuality, eapache seems to have the ability to see the value in AI research topics, but regardless is uninterested in the topic himself. But what you're describing would lead to eapache not being able to discern value or lack of value in AI research topics because he's uninterested and thus hasn't invested the time to be able to appreciate them.