Whats the deal with thumbs?

They are a way to express approval or disapproval of others' answers. You don't gain or lose points by giving or getting 'thumbs down'. Any answer you give a 'thumbs down' to becomes hidden to your view, but not to anyone else's, and you can opt to show it anyway. You don't gain any points by giving 'thumbs up' and only the answer chosen as 'best answer' gets one additional point for each 'thumbs up' received.