Currently, the comment for which I've received the most positive karma by a factor of four is a joke about institutionalized ass-rape. A secondhand joke, effectively a quote with no source cited. Furthermore, the comment had, at best, tangential relevance to the subject of discussion. If anyone were to provide a detailed explanation of why they voted as they did, I predict that I would be appreciative.
Based on this evidence, which priors need to be adjusted? Discuss.
I would say that karma measures the community's aggregate perception of worthiness, but does not define worthiness. My personal perception of worthiness reflects on the importance of the topic and the quality and novelty of the contribution to that topic.