With things like SO, Digg, Reddit, etc...
Should one keep track of downvotes in the database independent of upvotes? Or should they simply have a "votes" field that is decremented/incremented based off what the user does with no persisting of that?
How should votes be handled?
On SO, up votes earn +10, down votes -2. For this to work they need to be tracked separately. It's quite possible for a controversial answer to generate a few of each, and just showing an aggregate number won't mean much. So I'd say keep them separate.