Here are the comments he made in reference to removing average karma [1][2][3]:
> dang 781 days ago
> It's based on comment scores only. My sense is that it's an irrelevant distraction and we should get rid of it.
> For example, we caught a bunch of users who were gaming it by deleting any comments that brought their average down. We fixed that by treating deleted comments as comments of score 0 for average-computing purposes. It's an example of how, once you publish a metric, people start to care about it and do things based on it, regardless of how meaningful it is.
> Comment average used to be used by a few algorithms (like comment ranking) but we turned that off as an experiment a while ago and nothing seemed to get worse. If anything, I think it may have helped a little.
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> dang 572 days ago
> What brudgers said is correct, but I'll add that we're probably going to get rid of comment averages. We've looked at the data extensively and it hasn't proven to have much value. We've phased out the code that used to rely on it, and what's left (which is only for display) is probably not worth the cost.
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> dang 567 days ago
> ... We got rid of average because (a) after looking extensively at the data we didn't see any value in it, (b) we had evidence of people gaming the metric, (c) its implementation was complicated, and most importantly (d) we think upvotes are wrong thing to optimize for. Optimize for saying substantive things.
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[1]: https://news.ycombinator.com/item?id=9297678
[2]: https://news.ycombinator.com/item?id=8264220
[3]: https://news.ycombinator.com/item?id=9322256