I turned off Firefox's ability to save passwords because I trust my personal password keeper more than any internet browser, but I left the saving addresses feature on since that seemed handy. Wouldn't you know it though, Firefox considers a social security number an address. So now I need to hope that firefox doesn't get hacked by someone who knows how to use a social security number to rob me of everything I own. Nice.
In short, firefox should differentiate between addresses and social security numbers, and social security numbers should be included in passwords and not in addresses of all places.