Here's a crazy idea. What if down voting a comment/post resulted in a weighted random float between 0-1 while upvoting resulted in a weighted random float between 1-2? If you virulently hate a comment or post, ignoring it is the surest way to bury in completely. Posts and comments that Garner attention become the most visible, but gaming the system for visibility could become difficult if the weighting algorithm was tuned appropriately.