Rivets are a measure of how good looking you are. If you have 5, you are as good as it gets. Members with 1 should not go outside because you scare people. 2 means a good plastic surgeon might be able to help you.
Oh, maybe I have it wrong—5 means "don't believe anything this guy has to say, especially at 2:30 am".
But wait, it's the "do you have a life meter?" People with 5 rivets spend so much time on the Forum they don't have a life. You reach 5 rivets when you post 500 times. You look pale because you haven't been outside for 2 years and are living in your trailer.