[jwarden]

Yeah we have thought of a model where Karma is a measure of how much "marginal value" you have created for other users by your submissions. If we take upvotes as a proxy for value, we can calculate how many additional site-wide upvotes were generated as a result of you submitting your high-upvote-rate story: the number of upvotes your story received minus the number of upvotes the stories that were displace by your story being ranked above them would have received.

Then, we could allow you to spend a part of that value. That is, you can promote a story with a lower upvote rate, thereby decreasing site-wide upvotes by displacing stories with higher upvote rates. You would only be able to spend some fraction of the value you created, so that after you have spent all your Karma, the net value you have created for other users would still be positive.